CS & IT Solutions

Diskless client can be very useful for educational institutes, testing setups or the networks that have limited hardware resources available with them. Linux offers a robust diskless environment that can be configured on CentOS with ease.

Server Setup

To configure server we need (NFS, xinetd, tftp and dhcp server). I hope all these services already installed in your system. If you do not find these services in your system you can install all of them as follow

Create a directory on the NFS server to contain the diskless environment such as /diskless/i386/TECHBABU/ e.g

In the above configuration I have selected (TECHBABU) as operating identifier. You can change according to your need.

Configuring the NFS Server

Edit file /etc/exports

Next we need to start NFS Server

Let’s copy a running Linux OS in diskless environment through rsync utility. For example: Read the rest of this entry »

Text processing in Linux can be done using sed, cut, grep commands and with vi editor. We can find and replace a string, find and delete string etc.

Finding IP Addresses from Apache Log file through cut command

• The -d ‘-’ refers to delimeter –
• The -f1 is for first field in Apache log file

Remove particular IP Addresses from Apache log through sed command

• The -ie refers to inline edit in file
• The ‘/^10 indicates that IP must start with 10
• The \ indicates that special character . is text
• The /d indicates that delete this line

Remove lines containing a key word through sed

• The 1,30 refers to first 30 lines
• The {/index/d} indicates delete lines containing word “index”

Remove blank lines from a text file using vi editor

• The g refers globally
• The ^$/ d indicates delete blank lines

Remove special character # from a text file using vi editor

• The $s/ refers search from start
• The \# indicates take # as character
• The //g replace it with nothing i.e remove character

source here

Qmailtoaster is a project whose purpose is to install Qmail with RPMs on RPM based Linux and these RPMs are source RPMs. The advantage of Qmailtoaster is that it contains all patches needed for Qmail for example domainkeys etc.

Included Featureset by Qmailtoaster

• Source RPM packages easily rebuilt for multiple distributions
• SMTP with SMTP-AUTH, TLS, REMOTE-AUTH
• DomainKeys, SPF “Sender Policy Framework” and SRS “Sender Rewriting Scheme”
• Integrated SpamAssassin, ClamAV and Simscan
• Warlord virus and worm loader realtime MIME signature scanning
• CHKUSER 2.0 functions for qmail-smtpd
• Qmail-Tap provides email archive capability
• Virtual Domains and Virtual Users using MySQL
• Autoresponder for vacation/away from office messages
• Integrated Mailing List (ezmlm)
• Web-based email system using Squirrelmail
• Web-based administration tools
• POP3, POP3-SSL, IMAP and IMAP-SSL
• Submission port (587) allows roaming users to skip RBL checks and port 25 blocks
• eMPF patch for advanced policy control over email

Qmailtoaster has support for RHEL/CentOS (3.x, 4.x, 5.x , Fedora, Suse, Mandriva. We are going to install Qmailtoaster for CentOS 5.x

Prerequisites: Install Centos 5 base system, remaining packages and dependencies will be installed automatically with qmailtoaster scripts.

1) Configuration Read the rest of this entry »