Tcpdump command to monitor the SMTP activity from a IP or range of IP The tcpdump is a useful utility to monitor the network activity in the server. You can monitor the SMTP activity to find out the mail account used by spammer. tcpdump -i eth0 -n src 192.168.1.4 \or dst 192.168.1.4 -w smtp.tcpdump -s […]

You need to recompile kernel to enable IPTABLES support. I am giving the steps to enable IPTABLES support during kernel recompilation. Get into the kernel source directory: #  cd /usr/local/src/kernel<version> #  make menuconfig Select the following option (not as a loadable module) Networking >> Networking options >> Network packet filtering (replaces ipchains) >> Core Netfilter […]

A server is limited to a certain number of TCP/IP connections that it can keep track of. ip_conntrack is a module which has the limit set in its conntrack database. If the table exceeds this limit, even the legitimate packets will be dropped. We usually tweak this parameter in the sysctl.conf file. But if you […]

You can use the following steps to uninstall apf in a linux machine: Stop the apf service running in the server. $ /etc/rc.d/init.d/apf stop Remove the apf files from the server. $ rm -Rf /etc/apf $ rm -Rf /etc/rc.d/init.d/apf $ rm -Rf /var/log/apf_log $ rm -Rf /var/log/apfados_log $ rm -Rf /usr/local/sbin/apf Disable apf in the […]

It is sometimes easy to make changes in named.conf file or in any zone files manually though the control panel has options to modify them. If the changes are being made manually, we should also make sure that the configuration as well as the zone files are not being messed up. The bind package has […]

What is split DNS It is an advanced concept, and in which, the DNS server is configured to respond to the same query differently, based on the hosts accessing it. It is done by configuring different views or visibility in name server. A typical example is, how DNS server responds to the queries from the […]

What does the Status of my Domain name mean ? There are 23 domain name status codes that you may come across when using WHOIS. Most of these domain name status codes are variations of a few basic states. The following is a complete list of domain name status codes along with explanations/definitions for each […]

Free web hosting service It is a free of cost web hosting service and frequently advertisement-supported and of limited features. It will either provide a sub-domain (yoursite.example.com) or a directory on host’s site (www.example.com/~yourname). Shared web hosting service Here your web site is hosted on the same server where many other sites are their, ranging […]

You can use the following steps to uninstall apf on a linux machine: First stop the apf service.   # /etc/rc.d/init.d/apf stop Remove the apf files from the server.   # rm -Rf /etc/apf # rm -Rf /etc/rc.d/init.d/apf # rm -Rf /var/log/apf_log # rm -Rf /var/log/apfados_log # rm -Rf /usr/local/sbin/apf Disable apf in the run […]