what is outgoing/outbound connection source port & destination port ?

linuxcenter · 06-25-2013, 05:02 AM

i want to allow outgoing connection, mine is destination port or source port? who is destination here, my computer or the server/website im trying to connect & who is source.

eg :
iptables -A OUTPUT -o eth0 -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -i eth0 -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT

here dport 443 (is my port or the port of the computer im trying to connect)

inshort, INCOMING/INBOUND MEANS { FROM/SOURCE PORT /OTHERS PC - TO/DESTINATION PORT /MY PC }

OUTBOUND /OUTGOING MEANS ?
PLS REFER TO THE ABOVE EXAMPLE AND EXPLAIN

druuna · 06-25-2013, 05:15 AM

Maybe this will help clear things up a bit:

- iptables - source ? destination ? From where ? (here at LQ).

ali.abry · 06-25-2013, 06:00 AM

Code:

iptables -A OUTPUT -o eth0 -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT

when you want to connect to https , the data is going out of your computer (OUTPUT) have destination of port number 443 and its source can be any port number between 1024-65535 depending on what number your computer choosed . for example 2748 .

Code:

 iptables -A INPUT -i eth0 -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT

when any data comes from that https server to your computer (INPUT) in respond to your request it sourced from 443 port number and its destination can be any number from 1024-65535 for example 2748 .

its like a two way road .