How to Install and Configure MRTG on Ubuntu Server 12.04

This post will describe how to install and configure Tobi Oetiker’s MRTG (Multi Router Traffic Grapher) on your Ubuntu home server. Once configured, you’ll be able to use it to monitor the traffic in and out of your home network using the SNMP capability in your network’s gateway\router. MRTG generates static HTML pages containing PNG images which provide a visual representation of this traffic. MRTG typically produces daily, weekly, monthly, and yearly graphs. MRTG is written in perl and works on Unix/Linux as well as Windows. MRTG is free software licensed under the GNU GPL.

Software versions used in this post were as follows:

Ubuntu Server v12.04 x64 LTS)

mrtg_2.17.3-2ubuntu1_amd64.deb

Download and Install

First, download and install MRTG:

sudo apt-get install mrtg

If this is the first time installing MRTG on your server you’ll likely be presented with the following message. Answering “Yes” means that the default configuration file will be installed with permissions set at 640. Answering “No” means that the permissions are set at 644. In this example we’re going to accept the default Yes. No worries though, if you select No the steps in this tutorial will still work.

Download Offline Installers: Microsoft .NET Framework 4.0, 3.5 SP1, 3.5, 3.0 & 2.0 From Microsoft Servers

As many of the new Microsoft Windows applications are developed using .NET Framework, it is becoming mandatory to install .NET Framework on our personal computers.

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Microsoft provides .NET Framework installer as a free download available to everyone. But it is an online installer. That means, initially we have to download a small piece of installer and upon starting the installation process the installer automatically connects to Microsoft servers and downloads the required components and completes the installation.

The online installers works great as long as we have internet connectivity always. But many of us require offline installer to install the software on computers not connected to internet, to save the bandwidth while installing on many computers, etc.

How to Setup Chroot SFTP in Linux (Allow Only SFTP, not SSH)

If you want to setup an account on your system that will be used only to transfer files (and not to ssh to the system), you should setup SFTP Chroot Jail as explained in this article.

In a typical sftp scenario (when chroot sftp is not setup), if you use sftp, you can see root’s file as shown below.

If you want to give sftp access on your system to outside vendors to transfer files, you should not use standard sftp. Instead, you should setup Chroot SFTP Jail as explained below.

Non-Chroot SFTP Environment

In the following example (a typical sftp environment), abc can sftp to the system, and view /etc folder and download the files from there.

# sftp abc@xcessl0gycs.com
abc@xcessl0gycs's password:
sftp> pwd
Remote working directory: /home/abc

What’s the Difference Between 127.0.0.0 and 127.0.0.1?

Sometimes the most elementary of questions yield teachable moments; read on as we delve into how a single digit change between 127.0.0.0 to 127.0.0.1 offers a chance to look at network topology.

The Question

What’s the Difference Between 127.0.0.0 and 127.0.0.1?

I know that both are loopback IPs, but they have another ip mask.

What’s the difference between them? Can they be used interchangeably?

===========================================================================

IPv4 routes
===========================================================================
Active routes:
Destination               Mask          Gateway        Interface Metric
      0.0.0.0          0.0.0.0      192.168.1.1      192.168.1.6     26
[...]
    127.0.0.0        255.0.0.0         On-link         127.0.0.1    306
    127.0.0.1  255.255.255.255         On-link         127.0.0.1    306

What kind of information can we tease out from this table?

20+ .htaccess Hacks Every Web Developer Should Know About

Apache's .htaccess(hypertext access) configuration file can be a very powerful tool in a web developer's toolkit if used properly. It can be found in the webroot of your server and can be easily edited using any text editor. In this article I'm going to show you 20 .htaccess hacks and how to use them.

Before I start with this article I'd like to start by saying that abusing the .htaccess file will hurt the performance of your website. The .htaccess file should only be used if you have no other way to achieve certain things.

Make sure to back up your current .htaccess file before applying any of the following hacks.

1. Prevent Hotlinking

Tired of people using your bandwidth by putting the images hosted on your server on their website? Add the following code at the bottom of your .htaccess file to prevent hotlinking.

1	Options +FollowSymlinks

2	#Protect against hotlinking

3	RewriteEngine On

4	RewriteCond %{HTTP_REFERER} !^$

5	RewriteCond %{HTTP_REFERER} !^http://(www.)?domainname.com/ [nc]

6	RewriteRule .*.(gif|jpg|png)$http://domainname.com/img/stop_stealing_bandwidth.gif[nc]

NOTE: The following article explains better methods to "prevent" hotlinking:
Link building secrets by Maurizio Petrone

How to check what we have Installed in Debuian/Ubuntu OS

To check what have install by listing all using dpkg is easy.

dpkg -l

To check whether a package is install also easy.

dpkg -l | grep apache

The command above is some how redundant, because dpkg support wild characters, doing this instead

dpkg -l "apache*"

By doing this, it will also list the package that not install but available in dpkg cache, to install them you can simply apt-get. To indicate the packages installed it shows “ii” and not install shows “un”.

Shell Script File for Checking Package Installed or not Or If not then Install Package - For Ubuntu OS

Dpkg: check that unix package is installed. Bash script: install package if not present

dpkg -s can be used.

Example: is vlc installed?

> dpkg -s vlc|grep installed

Here is some logic in bash script, like installing package if it is not there:

1 2 3 4 5 6

problem=$(dpkg -s vlc|grep installed) echo Checking for libxul: $problem if [ "" == "$problem" ]; then echo "No libxul. Setting up libxul" sudo apt-get --force-yes --yes install vlc fi

How to Enable and Disable Root Login in Ubuntu 12.04 TLS

We have recently installed Ubuntu 12.10 Desktop and Ubuntu 12.10 Server, we have nowhere asked to supply root password during installation. Generally in Linux, root user does exist and we need to supply root password during installation. By default root account is disabled in Ubuntu Linux because of security reason and you cannot login as root user directly or su - (Switch User) to become a root. You need to add sudo (superuser do) before actual command if you want to run all administrative commands and you need to supply your password when prompts for password.

Sudo is allowed user to become superuser for temporary to run superuser administrative tasks.

During installation only allow to create new user which has no root ( aka super user) privileges. But same user is allowed to execute sudo commands. Configuring sudo access for users, need to configure /etc/sudoers.

We’ll be covering the usage of SUDO and also we are going to show you tips & tricks to become root user.

ADOBE ACROBAT X PRO 10.1.3 MULTILANGUAGE + KEYGEN

Adobe® Acrobat® X Pro software lets you deliver highly professional PDF communications. Create and edit PDF files with rich media included, share information more securely, and gather team feedback more efficiently.

Benefits of Acrobat X Pro

Increase your productivity : Get more work done — faster. From streamlining routine PDF tasks to quickly comparing two files, Acrobat X Pro software makes your job easier.

Protect sensitive information : Share files with confidence by easily adding PDF passwords or digital signatures. Remove sensitive information with redaction tools.

Easily create fillable forms : Turn your paper forms into fillable PDF forms in just a few steps. Distribute and collect forms electronically, track status, and analyze results.

Passive-interface command behavior in RIP, EIGRP & OSPF

Passive-interface command is used in all routing protocols to disable sending updates out from a specific interface. However the command behavior varies from o­ne protocol to another.

In RIP this command will disable sending multicast updates via a specific interface but will allow listening to incoming updates from other RIP speaking neighbors.

This simply means that the router will still be able to receive updates o­n that passive interface and use them in the routing table.

In EIGRP the passive-interface command stops sending outgoing hello packets, hence the router can not form any neighbor relationship via the passive interface. This behavior stops both outgoing and incoming routing updates.

In OSPF the passive-interface has a similar behavior to EIGRP. The command suppresses hello packets and hence neighbor relationships.