ipchains vs iptables
 

just simply.......
what exactly is the diff btw ipchains and iptables

".... [The] default Linux 2.4 kernel may use ipchains or iptables but not both. Iptables is the preferred firewall as it supports "state" and can recognize if a network connection has already been "ESTABLISHED" or if the connection is related to the previous connection (required for ftp which makes multiple connections on different ports). Ipchains can not. Ipchain rules take precedence over iptables rules. During system boot, the kernel attempts to activate ipchains, then attempts to activate iptables. If ipchain rules have been activated, the kernel will not start iptables.
"

http://www.yolinux.com/TUTORIALS/Lin...rkGateway.html

Differences Between iptables and ipchains

Firstly, the names of the built-in chains have changed from lower case to UPPER case, because the INPUT and OUTPUT chains now only get locally-destined and locally-generated packets. They used to see all incoming and all outgoing packets respectively.
The `-i' flag now means the incoming interface, and only works in the INPUT and FORWARD chains. Rules in the FORWARD or OUTPUT chains that used `-i' should be changed to `-o'.
TCP and UDP ports now need to be spelled out with the --source-port or --sport (or --destination-port/--dport) options, and must be placed after the `-p tcp' or `-p udp' options, as this loads the TCP or UDP extensions respectively (you may need to insert the ipt_tcp and ipt_udp modules manually).
The TCP -y flag is now --syn, and must be after `-p tcp'.
The DENY target is now DROP, finally.
Zeroing single chains while listing them works.
Zeroing built-in chains also clears policy counters.
Listing chains gives you the counters as an atomic snapshot.
REJECT and LOG are now extended targets, meaning they are separate kernel modules.
Chain names can be up to 16 characters.
MASQ and REDIRECT are no longer targets; iptables doesn't do packet mangling. There is a separate NAT subsystem for this: see the ipnatctl HOWTO.
Probably heaps of other things I forgot.

http://www.linuxguruz.com/iptables/h...s-HOWTO-7.html