Blocking Specific Sender to Specific Recipient or IPs Spamming Using Sendmail in Linux

July 9, 2010
Block Sendmail users

Maintaining a MailServer is really a all time headache for Mail Server Admins, specifically to prevent SPAM relayed from you Server or delivered to your server. In this article we would use some inbuilt feature of Sendmail to block users from sending mail to specific users or domains, this can be attained in many ways [...]

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Packet Capturing and Analayzing packets Using TCPDUMP on Centos, Fedora, Ubuntu and other Linux Distros

July 8, 2010

Many a times Linux System Admin2 face problem in network latency, connectivity the servers hampers the services which impact to the business. Using linux basic tools can not really solve it but you can identify the issues faced by the host to host or host to the device. Here we will be using tcpdump tool [...]

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Solved : Lock table is out of available locker entries – Yum install, yum upgrade

June 29, 2010

Recently faced a issue while installing a package using yum [root@back ~]# yum install mod-security rpmdb: Lock table is out of available locker entries rpmdb: Unknown locker ID: 3077 error: db4 error(22) from db->close: Invalid argument error: cannot open Packages index using db3 – Cannot allocate memory (12) error: cannot open Packages database in /var/lib/rpm [...]

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How to Install Mod Security on Linux Centos 5.4, Fedora 11-12

June 5, 2010

ModSecurity is a free open source Firewall for Web application which can help you to guard against Intrusion on your webservers like local file inclusion attacks, Cross Site Scripting, and SQL injection vulnerabilities and many more. The easiest way to install mod_security is using yum, to get the latest package of modsecurity refer to jason [...]

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Howto Add New User, New Group and modify Users, Groups in Linux – Centos5.4, Fedora 11 – Part 1

May 6, 2010

Adding users in Linux helps you from giving all user Administrative (root access) rights if the system is used by Multiple people. Its one of the basic command but still very important which need to studied in much details, The More detail you know about adding user and adding group modifying existing users and groups [...]

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Step by Step Installing mod_security from Source in Linux Centos5.4, Fedora12 Howto

May 5, 2010

To Install mod Security from the source go to the Website of Mod security and download the packages [superuser@ashwin modse]# get http://www.modsecurity.org/download/modsecurity-apache_2.5.12.tar.gz –2010-05-05 15:19:12– http://www.modsecurity.org/download/modsecurity-apache_2.5.12.tar.gz Saving to: `modsecurity-apache_2.5.12.tar.gz’ 100%[=======================================>] 1,392,209 1235.9Mb/s in 5s 2010-05-05 15:19:18 (1235.7 MB/s) – `modsecurity-apache_2.5.12.tar.gz’ saved [1392209/1392209] [superuser@ashwin modse]# tar -zxf modsecurity-apache_2.5.12.tar.gz [superuser@ashwin modse]# cd modsecurity-apache_2.5.12 Stop Apache httpd [superuser@ashwin modse]# [...]

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