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Question :
I’ve Redhat Enterprise Linux 5 server with Iptabeles firewall enabled. By default it is only allowing port 22. How do I open port 80 / 143 / 110 on Linux? I’ve started all services but don’t know how to open port using iptables.
Answer :
By default iptables firewall stores its configuration at /etc/sysconfig/iptables file. You need to edit this file and add rules to open port number. This file only avilable under Red Hat Enterprise Linux 3/4/5 and above
Open port 80
Open flle /etc/sysconfig/iptables :
vi /etc/sysconfig/iptables
Append rule as follows :
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
Save and close the file. Restart iptables :
/etc/init.d/iptables restart
Open port 110
Append rule as follows :
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 110 -j ACCEPT
Open port 143
Append rule as follows :
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 143 -j ACCEPT
Restart iptables service. Type the following command :
service iptables restart
Verify that port is open. Run following command :
netstat -tulpn | less
Make sure iptables is allowing port 80/110/143 connections :
iptables -L -n
Refer to iptables man page for more information about iptables usage and syntax :
man iptables
Sumber:
http[:]//www[.]cyberciti[.]biz/faq/howto-rhel-linux-open-port-using-iptables/