hi,
I want to install and configure router in mu linux box(RedHat 7.1).please suggest me the best.

are you looking for best router software or distro specific ?? get more detailed in what your wanting and makes it easier to answer.

hi,
I know that linux redhat 7.1 is a router and can be configured.If you can give me tips on that,no problem.If I want to download a new software and install as a router ,no problem.Please let me know which is the best,I'll try both.

i'm assuming you have two ethernet cards and want to route between a LAN on eth0 and a static IP on eth1.
IIf you want a good firewall on your router get bastille from bastille-linux.org

to set up routing
1. echo "1" > /proc/sys/net/ipv4/ip_forward
2.iptables -P FORWARD DENY
3. iptables -I FORWARD -s $LAN -d 0/0 -j ACCEPT
4.iptables -A FORWARD -s 0/0 -d $LAN -j ACCEPT
4 iptables -t nat -A POSTROUTING -s $LAN -j MASQUERADE

This is a very permissive setup . Bastille will set things up automatically when
you run InteractiveBastille.

If you want to run a router per se and not a firewall you'll probably need to use
the gated or routed packages to autonatically set up routes. BTW don't forget to set your default gateway etc . Check out Rusty's unreliable guides to NAT, firewalls at netfilter.samba.org
Hope this was helpful
penseur2

hi,
Thanks for you reply for setting routers.I installed two network cards(NICs) and set a seperate IP address for the two cards.I gave the command line configuration as you mentioned.But it throws error.I captured this error and I am sending you.
When I give
iptables -P FORWARD DENY ,it throws

/lib/modules/2.4.2-2/kernel/net/ipv4/netfilter/ip_tables.o: init_module: Device
or resource busy
Hint: insmod errors can be caused by incorrect module parameters, including invalid IO or IRQ parameters
/lib/modules/2.4.2-2/kernel/net/ipv4/netfilter/ip_tables.o: insmod /lib/modules/2.4.2-2/kernel/net/ipv4/netfilter/ip_tables.o failed
/lib/modules/2.4.2-2/kernel/net/ipv4/netfilter/ip_tables.o: insmod ip_tables failed
iptables v1.2.1a: can't initialize iptables table `filter': iptables who? (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

Please let me know what mistake is this or what should I do.

While I posted my pervious message,I did not see ipchain working.I stopped IPChain and re-typed your command line config.Now it says

iptable : Bad Policy name

Please suggest me what I should do.

I got that same error message in Red Hat 7.2