I'm reading examples for iptables, and I've got a pre-written file I'm using for the server that meets most of my needs. The format it uses to accept traffic on port 80 (for apache) is:
-A INPUT -p tcp --dport 80 -j ACCEPT
Another webpage I've read uses the following format to accept traffic for SMTP
-A INPUT -p tcp -s 0/0 --sport 1024:65535 -d server.ip.address.here --dport 25 -m state --state NEW,ESTABLISHED -j ACCEPT
Which seems a lot more complex? Is it necessary, or could I simply do:
-A INPUT -p tcp --dport 25 -j ACCEPT