Commands to open tcp or udp ports on the server

 Following commands use to open tcp or udp ports on the server:-

< Before using commands for opening the port,Please make sure the specific port is already opened & what is the use of that port >

You can verify the port with 

netstat -nap | grep : <port no>

(1)  You can open TCp port with.

iptables -A INPUT  -p tcp –dport <port no> -j ACCEPT

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(2) You can open UDP port with

iptables -A INPUT -p udp –sport <port no>  -j ACCEPT

after that

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(3) Service iptables save

and for flushhing iptables us

iptables -F 

 iptables -A INPUT -s 210.0.143.122 -j DROP

203.162.3.147

iptables -L

service iptables save

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THATS IT YOU DONE