This article is based on Outlook Expres,s but the procedure is very similar on all email clients. 1. Start your email client applications 2. Go to Tools > Accounts 3. Click on Add > Mail 4. Type in your name (this will be the name that appears as the sender of emails) and click Next. […]
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December 12th, 2011
How to redirect port using IPTABLES
You can redirect the port in IPTABLES using the prerouting parameter. Following is the command you can use to redirect the traffic of port 587 to port 25. $ /sbin/iptables -t nat -I PREROUTING -p tcp –dport 587 -j REDIRECT –to-port 25 $ /etc/init.d/iptables save $ /etc/init.d/iptables restart You can change the ports in the […]
December 12th, 2011
Tcpdump command to monitor the SMTP activity from a IP or range of IP
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 […]
December 12th, 2011
Enable IPTABLES support in Kernel(2.6.18)
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 […]
December 12th, 2011
Config Server Firewall (CSF) Installation
Tags: ConfigServer Firewall (csf) is a Stateful Packet Inspection (SPI) It is a firewall that keeps track of the state of network connections (such as TCP streams, UDP communication) travelling across it. The firewall is programmed to distinguish legitimate packets for different types of connections. Only packets matching a known connection state will be allowed by […]
December 12th, 2011
ip_conntrack and APF issue
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 […]
December 12th, 2011
How to uninstall apf in linux machine
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 […]
December 12th, 2011
named: the best practice in editing configuration files.
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 […]
December 12th, 2011
Split DNS
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 […]
December 12th, 2011
Unable to restart named
Getting the following errors while trying to restart named in a cPanel server. root@host [~]# service named restart Stopping named: [FAILED] Starting named: [FAILED] root@host [~]# service named status rndc: connection to remote host closed This may indicate that the remote server is using an older version of the command protocol, this host is not […]
