Linux Blimp

netdata is a extremely optimized Linux utility that provides real-time (per second) performance monitoring for Linux systems, applications, SNMP devices, etc. and shows full interactive charts that absolutely render all collected values over the web browser to analyze them.

Don’t Miss: 20 Useful Command-line Tools to Monitor Linux Performance

It has been developed to be installed on each Linux system, without interrupting the current running applications on it. You can use this tool to monitor and get overview of what is happening in real-time and what just happened, on your Linux systems and applications.

This is what it monitors:

1. Total and Per Core CPU usage, interrupts, softirqs and frequency.
2. Total Memory, RAM, Swap and Kernel usage.
3. Disk I/O (per disk: bandwidth, operations, backlog, utilization, etc).
4. Monitors Network interfaces including: bandwidth, packets, errors, drops, etc).
5. Monitors Netfilter / iptables Linux firewall connections, events, errors, etc.
6. Processes (running, blocked, forks, active, etc).
7. System Applications with the process tree (CPU, memory, swap, disk reads/writes, threads, etc).
8. Apache and Nginx Status monitoring with mod_status.
9. MySQL database monitoring: queries, updates, locks, issues, threads, etc.
10. Postfix email server message queue.
11. Squid proxy server bandwidth and requests monitoring.
12. Hardware sensors (temperature, voltage, fans, power, humidity, etc).
13. SNMP devices.

netdata Installation on Linux Systems

The latest release of netdata can be easily installed on Arch Linux, Gentoo Linux, Solus Linux and Alpine Linuxusing your package manager as shown.

$ sudo pacman -S netdata         [Install Netdata on Arch Linux]
$ sudo emerge --ask netdata      [Install Netdata on Gentoo Linux]
$ sudo eopkg install netdata     [Install Netdata on Solus Linux]
$ sudo apk add netdata           [Install Netdata on Alpine Linux]

On Debian/Ubuntu and RHEL/CentOS/Fedora, there is one line installation script that will install latest netdataand also keep it up to date automatically.

$ bash <(curl -Ss https://my-netdata.io/kickstart.sh            [On 32-bit]
$ bash <(curl -Ss https://my-netdata.io/kickstart-static64.sh)  [On 64-bit]

The above script will:

• discover the distribution and installs the needed software packages for building netdata (will ask for confirmation).
• downloads the latest netdata source tree to /usr/src/netdata.git.
• installs netdata by executing ./netdata-installer.sh from the source tree.
• installs netdata-updater.sh to cron.daily, so your netdata will be updated daily (you will receive a alert from cron only if the update fails).

Note: The kickstart.sh script progress all its parameters to netdata-installer.sh, so you can define more parameters to modify the installation source, enable/disable plugins, etc.

Alternatively, you can also install latest netdata manually by cloning its repository, but before you start installing netdata, make sure you have these basic build environment packages installed on the system, if not install it using your respective distribution package manager as shown:

On Debian / Ubuntu

# apt-get install zlib1g-dev gcc make git autoconf autogen automake pkg-config

On Centos / Redhat / Fedora

# yum install zlib-devel gcc make git autoconf autogen automake pkgconfig

Next, clone the netdata repository from git and run netdata installer script to build it.

# git clone https://github.com/firehol/netdata.git --depth=1
# cd netdata
# ./netdata-installer.sh

Note: The netdata-installer.sh script will build netdata and install it on your Linux system.

Once the netdata installer finishes, the file /etc/netdata/netdata.conf will be created in your system.

Now it’s time to start netdata by executing the following command from the terminal.

# /usr/sbin/netdata

You can also stop netdata by terminating it’s process with killall command as shown.

# killall netdata

Note: Netdata saves on exit its round robbin database information under /var/cache/netdata file, so that when you start again netdata, it will continue from where it was stopped last time.

Starting and Testing netdata

Now open your browser and navigate to the following address to access the web site for all graphs:

# http://127.0.0.1:19999/

Check out the video that shows how Real-time Linux performance monitoring done here: https://www.youtube.com/watch?v=QIZXS8A4BvI

You can also view the running configuration of netdata at any time, by going to:

http://127.0.0.1:19999/netdata.conf

Updating netdata

You can update netdata daemon to the most recent version by going into netdata.git directory you downloaded before and running:

# cd /path/to/netdata.git
# git pull
# ./netdata-installer.sh

The above netdata installer script will build new version and restart netdata.

Reference: https://github.com/firehol/netdata/

Source

Darkstat is a cross-platform, lightweight, simple, real-time network statistics tool that captures network traffic, computes statistics concerning usage, and serves the reports over HTTP.

Darkstat Features:

• An integrated web-server with deflate compression functionality.
• Portable, single-threaded and efficient Web based network traffic analyzer.
• The Web interface shows traffic graphs, reports per host and ports for each host.
• Supports asynchronous reverse DNS resolution using a child process.
• Support for IPv6 protocol.

Requirements:

• libpcap – a portable C/C++ library for network traffic capture.

Being small in size, it uses very low system memory resources and it is easy to install, configure and use in Linux as explained below.

How to Install Darkstat Network Traffic Analyzer in Linux

1. Luckily, darkstat is available in the software repositories of mainstream Linux distributions such as RHEL/CentOS and Debian/Ubuntu.

$ sudo apt-get install darkstat		# Debian/Ubuntu
$ sudo yum install darkstat		# RHEL/CentOS
$ sudo dnf install darkstat		# Fedora 22+

2. After installing darkstat, you need to configure it in the main configuration file /etc/darkstat/init.cfg.

$ sudo vi /etc/darkstat/init.cfg

Note that for the purpose of this tutorial, we will only explain mandatory as well as important configuration options for you to start using this tool.Now change the value of START_DARKSTAT from no to yes and set the interface darkstat will listen on with the INTERFACE option.

And also uncoment DIR=”/var/lib/darkstat” and DAYLOG=”–daylog darkstat.log” options to specify its directory and log file respectively.

START_DARKSTAT=yes
INTERFACE="-i ppp0"
DIR="/var/lib/darkstat"
# File will be relative to $DIR:
DAYLOG="--daylog darkstat.log"

3. Start the darkstat daemon for now and enable it to start at system boot as follows.

------------ On SystemD ------------ 
$ sudo systemctl start darkstat
$ sudo /lib/systemd/systemd-sysv-install enable darkstat
$ sudo systemctl status darkstat

------------ On SysV Init ------------
$ sudo /etc/init.d/darkstat start
$ sudo chkconfig darkstat on
$ sudo /etc/init.d/darkstat status

4. By default, darkstat listens on port 667, so open the port on firewall to allow access.

------------ On FirewallD ------------
$ sudo firewall-cmd --zone=public --permanent --add-port=667/tcp
$ sudo firewall-cmd --reload

------------ On IPtables ------------
$ sudo iptables -A INPUT -p udp -m state --state NEW --dport 667 -j ACCEPT
$ sudoiptables -A INPUT -p tcp -m state --state NEW --dport 667 -j ACCEPT
$ sudo service iptables save

------------ On UFW Firewall ------------
$ sudo ufw allow 667/tcp
$ sudo ufw reload

5. Finally access the darkstat web interface by going to URL http://Server-IP:667.

You can reload graphs automatically by clicking on and off buttons.

Manage Darkstat From Command Line in Linux

Here, we will explain a few important examples of how you can operate darkstat from the command line.

6. To collect network statistics on the eth0 interface, you can use the -i flag as below.

$ darkstat -i eth0

7. To serve web pages on a specific port, include the -p flag like this.

$ darkstat -i eth0 -p 8080

8. To keep an eye on network statistics for a given service, use the -f or filter flag. The specified filter expression in the example below will capture traffic concerned with SSH service.

$ darkstat -i eth0 -f "port 22"

Last but not least, if you want to shut darkstat down in a clean way; it is recommended to send SIGTERM or SIGINT signal to the darkstat parent process.

First get the darkstat parent process ID (PPID) using the pidof command:

$ pidof darkstat

Then kill the process like so:

$ sudo kill -SIGTERM 4790
OR
$ sudo kill -15 4790

For additional usage options, read through the darkstat manpage:

$ man darkstat

Reference Link: Darkstat Homepage

You may also like to read following related articles on Linux network monitoring.

1. 20 Command Line Tools to Monitor Linux Performance
2. 13 Linux Performance Monitoring Tools
3. Netdata – A Real-Time Linux Performance Monitoring Tools
4. BCC – Dynamic Tools for Linux Performance and Network Monitoring

That’s It! In this article, we have explained how to install and use darkstat in Linux to capture network traffic, calculates usage, and analyze reports over HTTP.

Do you have any questions to ask or thoughts to share, use the comment form below.

Source

The wc (word count) command in Unix/Linux operating systems is used to find out number of newline count, word count, byte and characters count in a files specified by the file arguments. The syntax of wc command as shown below.

# wc [options] filenames

The following are the options and usage provided by the command.

wc -l : Prints the number of lines in a file.
wc -w : prints the number of words in a file.
wc -c : Displays the count of bytes in a file.
wc -m : prints the count of characters from a file.
wc -L : prints only the length of the longest line in a file.

So, let’s see how we can use the ‘wc‘ command with their few available arguments and examples in this article. We have used the ‘tecmint.txt‘ file for testing the commands. Let’s find out the output of the file using cat command as shown below.

[root@tecmint ~]# cat tecmint.txt

Red Hat
CentOS
Fedora
Debian
Scientific Linux
OpenSuse
Ubuntu
Xubuntu
Linux Mint
Pearl Linux
Slackware
Mandriva

1. A Basic Example of WC Command

The ‘wc‘ command without passing any parameter will display a basic result of ”tecmint.txt‘ file. The three numbers shown below are 12 (number of lines), 16 (number of words) and 112 (number of bytes) of the file.

[root@tecmint ~]# wc tecmint.txt

12  16 112 tecmint.txt

2. Count Number of Lines

To count number of newlines in a file use the option ‘-l‘, which prints the number of lines from a given file. Say, the following command will display the count of newlines in a file. In the output the first filed assigned as count and second field is the name of file.

[root@tecmint ~]# wc -l tecmint.txt

12 tecmint.txt

3. Display Number of Words

Using ‘-w‘ argument with ‘wc‘ command prints the number of words in a file. Type the following command to count the words in a file.

[root@tecmint ~]# wc -w tecmint.txt

16 tecmint.txt

4. Count Number of Bytes and Characters

When using options ‘-c‘ and ‘-m‘ with ‘wc‘ command will print the total number of bytes and charactersrespectively in a file.

[root@tecmint ~]# wc -c tecmint.txt

112 tecmint.txt

[root@tecmint ~]# wc -m tecmint.txt

112 tecmint.txt

5. Display Length of Longest Line

The ‘wc‘ command allow an argument ‘-L‘, it can be used to print out the length of longest (number of characters) line in a file. So, we have the longest character line (‘Scientific Linux‘) in a file.

[root@tecmint ~]# wc -L tecmint.txt

16 tecmint.txt

6. Check More WC Options

For more information and help on the wc command, simple run the ‘wc –help‘ or ‘man wc‘ from the command line.

[root@tecmint ~]# wc --help

Usage: wc [OPTION]... [FILE]...
  or:  wc [OPTION]... --files0-from=F
Print newline, word, and byte counts for each FILE, and a total line if
more than one FILE is specified.  With no FILE, or when FILE is -,
read standard input.
  -c, --bytes            print the byte counts
  -m, --chars            print the character counts
  -l, --lines            print the newline counts
  -L, --max-line-length  print the length of the longest line
  -w, --words            print the word counts
      --help			display this help and exit
      --version			output version information and exit

Report wc bugs to bug-coreutils@gnu.org
GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
General help using GNU software: <http://www.gnu.org/gethelp/>
For complete documentation, run: info coreutils 'wc invocation'

Source

DHCP (short for Dynamic Host Configuration Protocol) is a client/server protocol that enables a server to automatically assign an IP address and other related configuration parameters (such as the subnet mask and default gateway) to a client on a network.

DHCP is important because it prevents a system or network administrator from manually configuring IP addresses for new computers added to the network or computers that are moved from one subnet to another.

The IP address assigned by a DHCP server to a DHCP client is on a “lease”, the lease time normally varies depending on how long a client computer is likely to require the connection or the DHCP configuration.

In this article, we will explain how to configure a DHCP server in CentOS and Ubuntu Linux distributions to assign IP address automatically to a client machine.

Installing DHCP Server in CentOS and Ubuntu

The DCHP server package is available in the official repositories of mainstream Linux distributions, installing is quite easy, simply run the following command.

# yum install dhcp		        #CentOS
$ sudo apt install isc-dhcp-server	#Ubuntu

Once the installation is complete, configure the interface on which you want the DHCP daemon to serve requests in the configuration file /etc/default/isc-dhcp-server or /etc/sysconfig/dhcpd.

# vim /etc/sysconfig/dhcpd		 #CentOS
$ sudo vim /etc/default/isc-dhcp-server	 #Ubuntu

For example, if you want the DHCPD daemon to listen on eth0, set it using the following directive.

DHCPDARGS=”eth0”

Save the file and exit.

Configuring DHCP Server in CentOS and Ubuntu

The main DHCP configuration file is located at /etc/dhcp/dhcpd.conf, which should contain settings of what to do, where to do something and all network parameters to provide to the clients.

This file basically consists of a list of statements grouped into two broad categories:

• Global parameters: specify how to carry out a task, whether to carry out a task, or what network configuration parameters to provide to the DHCP client.
• Declarations: define the network topology, state a clients is in, offer addresses for the clients, or apply a group of parameters to a group of declarations.

Now, open and edit the configuration file to configure your DHCP server.

------------ On CentOS ------------ 
# cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf	
# vi /etc/dhcp/dhcpd.conf	

------------ On Ubuntu ------------
$ sudo vim /etc/dhcp/dhcpd.conf				

Start by defining the global parameters which are common to all supported networks, at the top of the file. They will apply to all the declarations:

option domain-name "tecmint.lan";
option domain-name-servers ns1.tecmint.lan, ns2.tecmint.lan;
default-lease-time 3600; 
max-lease-time 7200;
authoritative;

Next, you need to define a sub-network for an internal subnet i.e 192.168.1.0/24 as shown.

subnet 192.168.1.0 netmask 255.255.255.0 {
        option routers                  192.168.1.1;
        option subnet-mask              255.255.255.0;
        option domain-search            "tecmint.lan";
        option domain-name-servers      192.168.1.1;
        range   192.168.10.10   192.168.10.100;
        range   192.168.10.110   192.168.10.200;
}

Note that hosts which require special configuration options can be listed in host statements (see the dhcpd.conf man page).

Now that you have configured your DHCP server daemon, you need to start the service for the mean time and enable it to start automatically from the next system boot, and check if its up and running using following commands.

------------ On CentOS ------------ 
# systemctl start dhcpd
# systemctl enable dhcpd
# systemctl enable dhcpd

------------ On Ubuntu ------------
$ sudo systemctl start isc-dhcp-server
$ sudo systemctl enable isc-dhcp-server
$ sudo systemctl enable isc-dhcp-server

Next, permit requests to the DHCP daemon on Firewall, which listens on port 67/UDP, by running.

------------ On CentOS ------------ 
# firewall-cmd --zone=public --permanent --add-service=dhcp
# firewall-cmd --reload 

#------------ On Ubuntu ------------
$ sudo ufw allow 67/udp
$ sudo ufw reload

Configuring DHCP Clients

Finally, you need to test if the DHCP server is working fine. Logon to a few client machines on the network and configure them to automatically receive IP addresses from the server.

Modify the appropriate configuration file for the interface on which the clients will auto-receive IP addresses.

DHCP Client Setup on CentOS

On CentOS, the interface config files ate located at /etc/sysconfig/network-scripts/.

# vim /etc/sysconfig/network-scripts/ifcfg-eth0

Add the options below:

DEVICE=eth0
BOOTPROTO=dhcp
TYPE=Ethernet
ONBOOT=yes

Save the file and restart network service (or reboot the system).

# systemctl restart network

DHCP Client Setup on Ubuntu

On Ubuntu 16.04, you can configure all interface in the config file /etc/network/interfaces.

   
$ sudo vi /etc/network/interfaces

Add these lines in it:

auto  eth0
iface eth0 inet dhcp

Save the file and restart network services (or reboot the system).

$ sudo systemctl restart networking

On Ubuntu 18.04, networking is controlled by the Netplan program. You need to edit the appropriate file under the directory /etc/netplan/, for example.

$ sudo vim /etc/netplan/01-netcfg.yaml 

Then enable dhcp4 under a specific interface for example under ethernets, ens0, and comment out static IP related configs:

network:
  version: 2
  renderer: networkd
  ethernets:
    ens0:
      dhcp4: yes

Save the changes and run the following command to effect the changes.

$ sudo netplan apply 

For more information, see the dhcpd and dhcpd.conf man pages.

$ man dhcpd
$ man dhcpd.conf

In this article, we have explained how to configure a DHCP server in CentOS and Ubuntu Linux distributions. If you need more clarification on any point, you can ask a question via the feedback form below, or simply share your comments with us.

Source

ProFTPD is an Open Source FTP Server and one of the most used, secure and reliable file transfer daemons on Unix environments, due to its file configurations simplicity speed and easy setup.

Requirements

1. CentOS 7 Minimal Installation
2. Red Hat Enterprise Linux 7 Installation
3. Configure Static IP Address on System

This tutorial will guide you on how you can install and use ProFTPD Server on CentOS/RHEL 7 Linux distributions for a simple file transfer from your local system accounts to remote systems.

Step 1: Install Proftpd Server

1. Official RHEL/CentOS 7 repositories doesn’t provide any binary package for ProFTPD Server, so you need to add extra package repositories on your system provided by EPEL 7 Repo, using the following command.

# rpm -Uvh http://ftp.astral.ro/mirrors/fedora/pub/epel/beta/7/x86_64/epel-release-7-0.2.noarch.rpm

2. Before you start installing ProFTPD Server, edit your machine hosts file, change it accordingly to your system FQDN and test the configurations to reflect your system domain naming.

# nano /etc/hosts

Here add your system FQDN on 127.0.0.1 localhost line like in the following example.

127.0.0.1 server.centos.lan localhost localhost.localdomain

Then edit /etc/hostname file to match the same system FQDN entry like in the screenshots below.

# nano /etc/hostname

3. After you have edited the host files, test your local DNS resolution using the following commands.

# hostname
# hostname -f    	## For FQDN
# hostname -s    	## For short name

4. Now it’s time to install ProFTPD Server on your system and some required ftp utilities that we will be using later by issuing following command.

# yum install proftpd proftpd-utils

5. After the server is installed, start and manage Proftpd daemon by issuing the following commands.

# systemctl start proftpd
# systemctl status proftpd
# systemctl stop proftpd
# systemctl restart proftpd

Step 2: Add Firewall Rules and Access Files

6. Now, your ProDTPD Server runs and listen for connections, but it’s not available for outside connections due to Firewall policy. To enable outside connections make sure you add a rule which opens port 21, using firewall-cmd system utility.

# firewall-cmd –add-service=ftp   ## On fly rule
# firewall-cmd –add-service=ftp   --permanent   ## Permanent rule
# systemctl restart firewalld.service 

7. The most simple way to access your FTP server from remote machines is by using a browser, redirecting to your server IP Address or domain name using ftp protocol on URL.

ftp://domain.tld

OR 

ftp://ipaddress 

8. The default configuration on Proftpd Server uses valid system local accounts credentials to login and access your account files which is your $HOME system path account, defined in /etc/passwd file.

9. To make ProFTPD Server automatically run after system reboot, aka enable it system-wide, issue the following command.

# systemctl enable proftpd

That’s it! Now you can access and manage your account files and folders using FTP protocol using whether a browser or other more advanced programs, such as FileZilla, which is available on almost any platforms, or WinSCP, an excellent File Transfer program that runs on Windows based systems.

Suggested Read: How to Install, Configure and Secure FTP Server in CentOS 7

On the next series of tutorials concerning ProFTPD Server on RHEL/CentOS 7, I shall discuss more advanced features like enabling Anonymous account, use TLS encrypted file transfers and adding Virtual Users.

Source

One important task in a network is control and manage staffs web surfing traffics, there are many solutions that can handles this issue, one of the best solutions is using squid cache on a Linux machine. Squid can inspect, limit and cache web traffics flow from one network to another network for example from a LAN to the Internet.

There is a few ways for redirecting client’s web requests to squid machine, in this article we will show you how to redirect web traffic from a CISCO router to a Squid Cache machine using WCCP protocol.

The picture below is an example of a basic scenario.

As you see in above picture all client’s web traffics first goes to Cisco Router (That is their default gateway), then router silently redirect packets to squid machine, now squid can play it’s roles, the main roles is caching web contents, limit access based on domains, time intervals, ip addresses, size of files, etc..

We review this scenario’s configuration in two Major steps, first we should install and configure squid and Linux, then configure router to redirecting web traffic packets into squid using WCCP protocol.

Testing Environment

In this scenario I use CENTOS 6.5 as my LINUX server and Cisco 2691 as my Router system.

Operating System: CENTOS 6.5
Application: Squid
Router: Cisco 2691

Step 1: Installing Squid Cache

Squid is available on default repository of CENTOS, we first install it using lovely yum command and then start their services and finally set automatic starting of squid service.

# yum -y install squid
# service squid start
# chkconfig squid on

Step 2: Preparing Squid Cache

Now we must change some default behaviors of centos operation system, we need to enable packet forwarding and disable reverse Path filter (RPF), we enable packet forwarding to let the centos acting as a transparent forwarder (like a router).

Let me explain in more detail, when traffics gets in centos it have their source and destination addresses, for example when a client enter www.example.com on his/her browser a http request packet generates and it have source ip address of client machine (like 192.168.1.20) and destination ip address of example.com server (like 2.2.2.2).

So, when packet received by centos it detect as an wrong packet because centos ip address is not as destination address of the packet, for security reasons centos drop the packet, but we want from squid to act in transparent mode. We tell this situation to centos by enabling packet forwarding potion.

Next we should disable Reverse path Filtering to let the centos accepting packets that not accessible by squid machine or it packets that do not have ip address in the same subnet of squid machine.

# nano /etc/sysctl.conf

net.ipv4.ip_forward = 1 #set to 1 for enable the packet forwarding feature
net.ipv4.conf.default.rp_filter = 0 # set to 0 for disable the reverse path filter behavior

Next we need to create a GRE interface on CENTOS machine, for what?? Let me explain more, the WCCPprotocol works through a GRE Tunnel, it means the language between router and Squid is GRE, so centos need to have a GRE interface for De-encapsulate GRE packets.

We should create the configuration file for GRE interface in “/etc/sysconfig/network-script/ifcfg-gre0” path.

Enter below codes in ifcfg-gre0 configuration file.

DEVICE=gre0
BOOTPROTO=static
IPADDR=10.0.0.2         #unused ip address in your network
NETMASK=255.255.255.252
ONBOOT=yes
IPV6INIT=no

After creating a GRE interface we need to restart network service.

# service network restart

Step 3: Configuring Squid Cache

We need to tell squid accepting WCCP packets from router. Enter below codes in /etc/squid/squid.conf file.

http_port 3128 intercept                 # Define SQUID listening port
wccp2_router 192.168.1.254          #ip address of the router
wccp2_forwarding_method gre
wccp2_return_method gre
wccp2_service standard 0

Save the configuration file and restart squid service.

# service squid restart

Squid listen for packets in 3128 port, but our packet’s destination port number is 80, so for changing destination port 80 to 3128, we need to create a NAT rule on CENTOS integrated firewall (that named iptable).

# iptables -t nat -A PREROUTING -i gre0 -p tcp --dport 80 -j REDIRECT --to-port 3128
# iptables -t nat -A POSTROUTING -j MASQUERADE

Step 4: Cisco Router Configurations

First we should enable WCCP on cisco router.

R1(config)# ip wccp version 2
Then we must use an ACL for introducing SQUID cache machine to router
R1(config)# ip access-list standard SQUID-MACHINE
R1(config-std-nacl)# permit host 192.168.1.10

Next we define another access list for two different purpose first we should except SQUID traffics from redirecting by WCCP protocol (if not we fall into an infinite loop!!) second we define which LAN traffics we want to passing through WCCP and SQUID.

R1(config)#ip access-list LAN-TRAFFICS
R1(config-ext-nacl)#deny ip host 192.168.1.10 any                            #Prevent SQUID to get in loop
R1(config-ext-nacl)#permit tcp 192.168.1.0 0.0.0.255 any equal www           #define LAN Traffics

After creating our access-list we must configure WCCP protocol on router.

R1(config)# ip wccp web-cache redirect-list LAN-TRAFFIC group-list SQUID-MACHINE

Every things is ready for final step, we must tell the router that in which interface/interfaces it must redirect traffics using their WCCP configuration.

R1(config)#interface fastEthernet 0/0
R1((config-if)# ip wccp web-cache redirect in

Summary

It’s time to summarize all commands and texts in a few lines for better understanding, according to the scenario we redirect staffs web surfing packets (that is on TCP port 80) from the ROUTER (that is default gateway of the clients) toward the squid cache machine using WCCP protocol.

All these process happened silently and there is no additional configuration on client side. So we can control and set policies on web traffics in the LAN. For example, we can gain web surfing access just in a limited time, limit maximum download size, define our custom blacklist and whitelist, generate full reports of internet activity usage and etc.

One of the interesting facts in this scenario is when squid machine goes down router detect this issue and stop redirecting packets toward it, so you can enjoy from zero-downtime in your network.

If you have any questions regarding to this article please leave a reply through below comment box.

Source

Streaming media becomes more and more popular in recent years. Many people like to access their audio and video media from different locations and devices. With Plex Media Server you can easily achieve exactly that (and more) on practically any platform.

There are two versions of Plex – free and paid one.

Plex Free Version

Let’s have a look at what you can do with Plex Media Server (free):

• Stream your audio and video content
• Includes web app to access your content
• Organize libraries
• News and podcasts
• Mobile app (with limited access)
• Voice control
• Available anywhere
• PlexApp for remote control
• 4K support
• Media optimization for buffer free streaming

Plex Paid Version

The paid version of Plex, called Plex Pass, adds the following features:

• Live TV and DVR
• Stream trailers and extras. Also add lyrics to your songs, from LyricFind
• Have geographic and scene-based tags on your photos
• Use mobile sync for offline use
• Camera upload for wireless syncing of photos
• Sync content to multiple Cloud providers
• Setup Plex Home to share content with your family and restrict what content can be accessed from your server
• Unlock mobile features
• Photo albums and Timeline view

It depends on you if you want to spend your hard earned money on the paid version of Plex, given the fact that the free version already provides lots of cool features.

Note that in order to use Plex, you will need to have an active account, that you can create here. The process is simple and straightforward so we will not stop to review the account creation.

Installing Plex Media Server in CentOS 7

Installing Plex is relatively easy task. Before we start, make sure your system is up to date by running:

$ sudo yum update

Next, head to Plex downloads page and download the package for your Linux distro. It is much easier to do this by simply coping the download link location with right click and then you can run:

$ sudo rpm -ivh https://downloads.plex.tv/plex-media-server/1.13.8.5395-10d48da0d/plexmediaserver-1.13.8.5395-10d48da0d.x86_64.rpm

Alternatively, you can download the package on your system with wget command as shown.

$ wget https://downloads.plex.tv/plex-media-server/1.13.8.5395-10d48da0d/plexmediaserver-1.13.8.5395-10d48da0d.x86_64.rpm

Use yum command to install the Plex server.

Now ensure that Plex is automatically started after system reboot and start the service.

$ sudo systemctl enable plexmediaserver.service
$ sudo systemctl start plexmediaserver.service

Configure Plex Media Server in CentOS 7

Plex comes with a pre-install web interface, through which you can manage your server. It can be accessed at:

http://[your-server-ip-address]:32400/web/

In my case this is:

http://192.168.20.110:32400/web/

You will be asked to login with your Plex account. When you authenticate, you will see a couple of windows regarding how Plex works and the second one providing you with list of paid options.

Lets head to the next one, where we can configure our server name. You can input whatever you like here:

Next you can organize your media library. Simply click the “Add library” button and navigate to your media.

Once you have configured your media library, you are all set and can complete the setup.

If you have skipped the media library setup, you can add more media later by clicking the plus “+” sign next to library in the left side menu. When configuring your media, it might come useful to check Plex’s naming convention here.

If you have setup Plex on a public server, it is recommended to disable DLNA as it will be accessible on port 1900. If you have setup Plex on a home server, you can leave it enabled so that media from your server is shared across devices in the same network.

To enable or disable DLNA click on “Settings” in the upper left corner and then scroll down to “DLNA”. From there you can check the box to enable or uncheck to disable DLNA:

Connect to Your Plex Server

Now that your media server is up and running, only thing left to do is:

• Download the appropriate client to connect to your server. This can be done from your phone, PC, Mac etc.
• Authenticate in the app with the same credentials you have used for your Plex server.
• Start enjoying your media.

Plex is an easy to use, feature rich media server to help you enjoy your media from almost every device and place.

Source

The following tutorial aims to provide you a simple step-by-step guide for setting up MySQL (Master-Slave) Replication in RHEL 6.3/6.2/6.1/6/5.8, CentOS 6.3/6.2/6.1/6/5.8 and Fedora 17,16,15,14,13,12 using latest MySQL version. This guide is specially written for CentOS 6.3 Operating System, but also work with older version of Linux distributions with MySQL 5.x.

UPDATE: If you’re looking for MariaDB Master-Slave Replication under CentOS/RHEL 7 and Debian 8 and it’s derivatives such as Ubuntu, follow this guide Setup MariaDB Master-Slave Replication.

The MySQL Replication is very useful in terms of Data Security, Fail-over Solution, Database Backup from Slave, Analytics etc. We use the following things to carry the replication process. In your scenario it would be different.

1. Working Linux OS like CentOS 6.3, RedHat 6.3 or Fedora 17
2. Master and Slave are CentOS 6.3 Linux Servers.
3. Master IP Address is: 192.168.1.1.
4. Slave IP Address is: 192.168.1.2.
5. Master and Slave are on the same LAN network.
6. Master and Slave has MySQL version installed.
7. Master allow remote MySQL connections on port 3306.

We have two servers, one is Master with IP (192.168.1.1) and other is Slave as (192.168.1.2). We have divided the setup process in two phases to make things easier for you, In Phase I we will configure Master server and in Phase II with Slave server. Let’s start the replication setup process.

Phase I: Configure Master Server (192.168.1.1) for Replication

In Phase I, we will see the installation of MySQL, setting up Replication and then verifying replication.

Install a MySQL in Master Server

First, proceed with MySQL installation using YUM command. If you already have MySQL installation, you can skip this step.

# yum install mysql-server mysql

Configure a MySQL in Master Server

Open my.cnf configuration file with VI editor.

# vi /etc/my.cnf

Add the following entries under [mysqld] section and don’t forget to replace tecmint with database name that you would like to replicate on Slave.

server-id = 1
binlog-do-db=tecmint
relay-log = /var/lib/mysql/mysql-relay-bin
relay-log-index = /var/lib/mysql/mysql-relay-bin.index
log-error = /var/lib/mysql/mysql.err
master-info-file = /var/lib/mysql/mysql-master.info
relay-log-info-file = /var/lib/mysql/mysql-relay-log.info
log-bin = /var/lib/mysql/mysql-bin

Restart the MySQL service.

# /etc/init.d/mysqld restart

Login into MySQL as root user and create the slave user and grant privileges for replication. Replace slave_userwith user and your_password with password.

# mysql -u root -p

mysql> GRANT REPLICATION SLAVE ON *.* TO 'slave_user'@'%' IDENTIFIED BY 'your_password';
mysql> FLUSH PRIVILEGES;
mysql> FLUSH TABLES WITH READ LOCK;
mysql> SHOW MASTER STATUS;

+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000003 | 11128001 | tecmint		 |                  |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)

mysql> quit;

Please write down the File (mysql-bin.000003) and Position (11128001) numbers, we required these numbers later on Slave server. Next apply READ LOCK to databases to export all the database and master database information with mysqldump command.

#  mysqldump -u root -p --all-databases --master-data > /root/dbdump.db

Once you’ve dump all the databases, now again connect to mysql as root user and unlcok tables.

mysql> UNLOCK TABLES;
mysql> quit;

Upload the database dump file on Slave Server (192.168.1.2) using SCP command.

scp /root/dbdump.db root@192.168.1.2:/root/

That’s it we have successfully configured Master server, let’s proceed to Phase II section.

Phase II: Configure Slave Server (192.168.1.2) for Replication

In Phase II, we do the installation of MySQL, setting up Replication and then verifying replication.

Install a MySQL in Slave Server

If you don’t have MySQL installed, then install it using YUM command.

# yum install mysql-server mysql

Configure a MySQL in Slave Server

Open my.cnf configuration file with VI editor.

# vi /etc/my.cnf

Add the following entries under [mysqld] section and don’t forget to replace IP address of Master server, tecmint with database name etc, that you would like to replicate with Master.

server-id = 2
master-host=192.168.1.1
master-connect-retry=60
master-user=slave_user
master-password=yourpassword
replicate-do-db=tecmint
relay-log = /var/lib/mysql/mysql-relay-bin
relay-log-index = /var/lib/mysql/mysql-relay-bin.index
log-error = /var/lib/mysql/mysql.err
master-info-file = /var/lib/mysql/mysql-master.info
relay-log-info-file = /var/lib/mysql/mysql-relay-log.info
log-bin = /var/lib/mysql/mysql-bin

Now import the dump file that we exported in earlier command and restart the MySQL service.

# mysql -u root -p < /root/dbdump.db
# /etc/init.d/mysqld restart

Login into MySQL as root user and stop the slave. Then tell the slave to where to look for Master log file, that we have write down on master with SHOW MASTER STATUS; command as File (mysql-bin.000003) and Position (11128001) numbers. You must change 192.168.1.1 to the IP address of the Master Server, and change the user and password accordingly.

# mysql -u root -p

mysql> slave stop;
mysql> CHANGE MASTER TO MASTER_HOST='192.168.1.1', MASTER_USER='slave_user', MASTER_PASSWORD='yourpassword', MASTER_LOG_FILE='mysql-bin.000003', MASTER_LOG_POS=11128001;
mysql> slave start;
mysql> show slave status\G

*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.1
                  Master_User: slave_user
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000003
          Read_Master_Log_Pos: 12345100
               Relay_Log_File: mysql-relay-bin.000002
                Relay_Log_Pos: 11381900
        Relay_Master_Log_File: mysql-bin.000003
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: tecmint
          Replicate_Ignore_DB:
           Replicate_Do_Table:
       Replicate_Ignore_Table:
      Replicate_Wild_Do_Table:
  Replicate_Wild_Ignore_Table:
                   Last_Errno: 0
                   Last_Error:
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 12345100
              Relay_Log_Space: 11382055
              Until_Condition: None
               Until_Log_File:
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File:
           Master_SSL_CA_Path:
              Master_SSL_Cert:
            Master_SSL_Cipher:
               Master_SSL_Key:
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error:
               Last_SQL_Errno: 0
               Last_SQL_Error:
1 row in set (0.00 sec)

Verifying MySQL Replication on Master and Slave Server

It’s really very important to know that the replication is working perfectly. On Master server create table and insert some values in it.

On Master Server

mysql> create database tecmint;
mysql> use tecmint;
mysql> CREATE TABLE employee (c int);
mysql> INSERT INTO employee (c) VALUES (1);
mysql> SELECT * FROM employee;

+------+
|  c  |
+------+
|  1  |
+------+
1 row in set (0.00 sec)

On Slave Server

Verifying the SLAVE, by running the same command, it will return the same values in the slave too.

mysql> use tecmint;
mysql> SELECT * FROM employee;

+------+
|  c  |
+------+
|  1  |
+------+
1 row in set (0.00 sec)

That’s it, finally you’ve configured MySQL Replication in a few simple steps. More information can be found at MySQL Replication Guide.

Source

Mytop is an open source and free monitoring program for MySQL and MariaDB databases was written by Jeremy Zawodny using Perl language. It is much similar in look and feel of the most famous Linux system monitoring tool called top.

Mytop program provides a command-line shell interface to monitor real time MySQL/MariaDB threads, queries per second, process list and performance of databases and gives a idea for the database administrator to better optimize the server to handle heavy load.

By default Mytop tool is included in the Fedora and Debian/Ubuntu repositories, so you just have to install it using your default package manager.

If you are using RHEL/CentOS distributions, then you need to enable third party EPEL repository to install it.

For other Linux distributions you can get mytop source package and compile it from source as shown.

# tar -zxvf mytop-<version>.tar.gz
# cd mytop-
# perl Makefile.PL
# make
# make test
# make install

In this MySQL monitoring tutorial, we will show you how to install, configure and use mytop on various Linux distributions.

Please note you must have running MySQL/MariaDB Server on the system to install and use Mytop.

Install Mytop in Linux Systems

To install Mytop, run the appropriate command below for your Linux distribution to install it.

$ sudo apt install mytop	#Debian/Ubuntu
# yum install mytop	        #RHEL/CentOS
# dnf install mytop	        #Fedora 22+
# pacman -S mytop	        #Arch Linux 
# zypper in mytop	        #openSUSE

Sample Output :

Loaded plugins: changelog, fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.linode.com
 * epel: mirror.freethought-internet.co.uk
 * extras: mirrors.linode.com
 * updates: mirrors.linode.com
Resolving Dependencies
--> Running transaction check
---> Package mytop.noarch 0:1.7-10.b737f60.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==============================================================================================================================================================================
 Package                               Arch                                   Version                                              Repository                            Size
==============================================================================================================================================================================
Installing:
 mytop                                 noarch                                 1.7-10.b737f60.el7                                   epel                                  33 k

Transaction Summary
==============================================================================================================================================================================
Install  1 Package

Total download size: 33 k
Installed size: 68 k
Is this ok [y/d/N]: y

How to use Mytop to Monitor MySQL/MariaDB

Mytop needs MySQL/MariaDB login credentials to monitor databases and connects to the server with the root username by default. You can specify the necessary options for connecting to the database server on the command-line as you run it or in the file ~/.mytop (for convenience as explained later on).

Just run the following command to start the mytop and provide your MySQL/MariaDB root user password, when prompted. This will connect to the test database by default.

# mytop --prompt
Password:

Once you entered the MySQL root password you will see Mytop monitoring shell, similar to below.

If you would like to monitor specific database, then use the -d option as shown below. For example the below command will monitor database tecmint.

# mytop --prompt -d tecmint
Password:

If each of your databases has a specific admin (for example tecmint database admin), then connect using the database username and password like so.

# mytop -u tecmint -p password_here -d tecmintdb

However, this has certain security implications since the user’s password is typed on the command-line and can be stored in the shell command history file. This file can be viewed later on by an unauthorized person who might land on the username and password.

To avoid the risk of such a scenario, use the ~/.mytop config file to specify options for connecting to the database. Another advantage of this method is that you also do away with typing numerous command-line arguments each time you want to run mytop.

# vi ~/.mytop

Then add the necessary options below in it.

user=root
pass=password_here
host=localhost
db=test
delay=4
port=3306
socket=

Save and close the file. Then run mytop without any command-line arguments.

# mytop

It has a capability to show large amount of information on the screen and has many keyboard shortcut options too, check out “man mytop” for more information.

# man mytop

Read Also :

1. Mtop (MySQL Database Monitoring) in RHEL/CentOS/Fedora
2. Innotop to Monitor MySQL Performance

In this article, we have explained how to install, configure and use mytop in Linux. If you have any questions, use the feedback form below to reach us.

Source

mtop (MySQL top) is an open source real time MYSQL Server monitoring program written in Perl language that shows queries which are taking longer time to process and kills those longer queries after certain number of specified time. Mtop program enable us to monitor and identify performance and related issues of MySQL Server from the command line interface similar to Linux Top Command.

Mtop includes zooming feature that display query optimizer information of a running queries and killing queries, it also shows statistics of server, configuration information and some useful tuning tips to optimize and improve MySQL performance.

Please check some of the following features offered by Mtop program.

1. Display real time MySQL server queries.
2. Provides MySQL configuration information.
3. Zooming feature to display process query.
4. Provides query Optimizer information for a query and ‘killing’ queries.
5. Provides MySQL tuning tips.
6. Ability to save output in a .mtoprc configuration file.
7. Provides Sysadmin recommendation page (‘T‘).
8. Added queries/second to main header.
9. Added per second info to stats screen.

In this article we’re going to show how to install Mtop (MySQL Top) program under RHEL 7/6.3/6.2/6.1/6/5.8/5.6/4.0, CentOS 7/6.3/6.2/6.1/6/5.8/5.6/4.0 and Fedora 17,16,15,14,13,12 using RPMForgerepository via YUM Command.

Enable RPMForge Repository in RHEL/CentOS 6/5/4 and Fedora 17-12

First, you need to enable RPMForge repository under your Linux machine to download and install latest version of MTOP program.

Install RPMForge on RHEL/CentOS 6

Select the following links based on your Linux architecture to enable RPMforge repository under your Linux box. (Note : Fedora user’s don’t need to enable any repository under Fedora box).

For RHEL/CentOS 6 32-Bit OS

# wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.i686.rpm
# rpm -Uvh rpmforge-release-0.5.2-2.el6.rf.i686.rpm

For RHEL/CentOS 6 64-Bit OS

# wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
# rpm -Uvh rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm

Install RPMForge on RHEL/CentOS 5

For RHEL/CentOS 5 32-Bit OS

# wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.i386.rpm
# rpm -Uvh rpmforge-release-0.5.2-2.el5.rf.i386.rpm

For RHEL/CentOS 5 64-Bit OS

# wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.x86_64.rpm
# rpm -Uvh rpmforge-release-0.5.2-2.el5.rf.x86_64.rpm

Install RPMForge on RHEL/CentOS 4

For RHEL/CentOS 4 32-Bit OS

# wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el4.rf.i386.rpm
# rpm -Uvh rpmforge-release-0.5.2-2.el4.rf.i386.rpm

For RHEL/CentOS 4 64-Bit OS

# wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el4.rf.x86_64.rpm
# rpm -Uvh rpmforge-release-0.5.2-2.el4.rf.x86_64.rpm

Import RPMForge Repository Key in RHEL/CentOS 6/5/4

# wget http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt
# rpm --import RPM-GPG-KEY.dag.txt

Install Mtop in RHEL/CentOS 6/5/4 and Fedora 17-12

Once you’ve installed and enabled RPMForge repository, let’s install MTOP using following YUM command.

# yum install mtop

Sample Output :

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
rpmforge                                                                          | 1.9 kB     00:00
rpmforge/primary_db                                                                 2.6 MB     00:19
Setting up Install Process
Dependencies Resolved

================================================================================================================
 Package                       Arch				Version					Repository				Size
================================================================================================================
Installing:
 mtop                          noarch           0.6.6-1.2.el6.rf        rpmforge                52 k
Installing for dependencies:
 perl-Curses                   i686             1.28-1.el6.rf           rpmforge                156 k

Transaction Summary
================================================================================================================
Install       2 Package(s)

Total download size: 208 k
Installed size: 674 k
Is this ok [y/N]: y
Downloading Packages:
(1/2): mtop-0.6.6-1.2.el6.rf.noarch.rpm                                           |  52 kB     00:00
(2/2): perl-Curses-1.28-1.el6.rf.i686.rpm                                         | 156 kB     00:01
-----------------------------------------------------------------------------------------------------------------
Total                                                                     46 kB/s | 208 kB     00:04
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
  Installing : perl-Curses-1.28-1.el6.rf.i686													1/2
  Installing : mtop-0.6.6-1.2.el6.rf.noarch                                                     2/2
  Verifying  : perl-Curses-1.28-1.el6.rf.i686                                                   1/2
  Verifying  : mtop-0.6.6-1.2.el6.rf.noarch                                                     2/2

Installed:
  mtop.noarch 0:0.6.6-1.2.el6.rf

Dependency Installed:
  perl-Curses.i686 0:1.28-1.el6.rf

Complete!

Starting Mtop in RHEL/CentOS 6/5/4

To start Mtop program, you need to connect to your MySQL Server, using following command.

# mysql -u root -p

Then you need to create separate user called mysqltop and grant privileges to him under your MySQL server. To do, this just run the following commands in mysql shell.

mysql> grant super, reload, process on *.* to mysqltop;
Query OK, 0 rows affected (0.00 sec)

mysql> grant super, reload, process on *.* to mysqltop@localhost;
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> quit;
Bye

Running Mtop in RHEL/CentOS 6/5/4

Let’s start the Mtop program by executing below command. You will see sample output similar to below.

# mtop

Sample Outpit :

load average: 0.01, 0.00, 0.00 mysqld 5.1.61 up 5 day(s), 19:21 hrs
2 threads: 1 running, 0 cached. Queries/slow: 5/0 Cache Hit: 71.43%
Opened tables: 0  RRN: 277  TLW: 0  SFJ: 0  SMP: 0  QPS: 0

ID       USER     HOST         DB       TIME   COMMAND STATE        INFO
322081   mysqltop localhost						Query				show full processlist

Monitor Remote MySQL Server using Mtop

Simply, type the following command to monitor any remote MySQL Server.

# mtop  –host=remotehost –dbuser=username –password=password –seconds=1

Mtop Usage and Functions

Please use the following keys while mtop is running.

Filtering/display

1. s – change the number of seconds to delay between updates
2. m – toggle manual refresh mode on/off
3. d – filter display with regular expression (user/host/db/command/state/info)
4. F – fold/unfold column names in select statement display
5. h – display process for only one host
6. u – display process for only one user
7. i – toggle all/non-Sleeping process display
8. o – reverse the sort order
9. q – quit
10. ? – help

For more options and usage please see the man pages of mtop command by running “man mtop” on terminal.

Read Also :

1. Mytop Database Monitoring
2. Innotop to Monitor MySQL Performance

Source