blocking and allowing ports
 

how would i go about making a small custom firewall? i have a txt file containing a list of ports along with an action stating whether to allow an IN, OUT, or BOTH connection. i understand i need to create a system call and/or modify the tcp_v4_rcv function but am unclear. can someone help me along or assist me in another approach? thanks!

hi there

shorewall is easy and a good firewall
have look at
shorewall.org and chek out its docs

regards

thanks but i dont want a program. i need to make it myself (its also for a project) and i'm relatively new to linux. i just need to understand how to block and allow ports using the structaddr module

Guarddog (which requires some of the KDE stuff, but not the KDE desktop) is what I use. It makes it easy to customize iptables however you want your firewall set up.

Everything you need to know --> Netfilter