hi,

i have a linux system configured as router with 3 nic's 192.168.85.254, 192.168.1.254, 192.168.2.254

192.168.85.0 network 1
192.168.1.0 network 2
192.168.2.0 network 3

i configured below rule so that 192.168.1.0 and 192.168.2.0 clients communicate with 192.168.85.0 network.

Now my requirement is to stop 192.168.1.0 to comminicate / ping 192.168.85.0 so i did

it's working, my doubt is, if it's proper way to do to get my purpose served or is there any other way i mean.., removing the completely and write another rule to make 192.168.2.0 communicate with 192.168.85.0

please help me

thank you.......

if you want a connection to not be possible, explicitly blocking is always the best way. I would say your approach is preferable that simply putting in a configuration that omits some functionality. They'd both do the same job really, but an explicit deny is easier to read and more secure.

Hi acid_kewpie,

I don't get u, if you say i'm correct...thanks for your reply. By the way please look at the below thread.

http://www.linuxquestions.org/questi...ks-4175417938/
I posted this many time's but u never come accross my thread, my badluck. Please go through it. I want to buil a router to join 4 networks with a linux system using 4 lan cards, enabled ip forward in /etc/sysctl.conf. What i'm stucking at iptables.i know i should use masquerade. my doubt is do i have to apply rule for all the four cards ?

please help me. really need at my work...

thank you very much ...

In most cases, you would only enable MASQUERADE on an interface which is directly connected to the internet. In your other thread you suggest that you don't have an internet connection, is this correct?

hi SuperJediWombat!,

thanks for your reply, i think i confused. i was talking about squid as an example plese leave it in this post. Now i'll tell you my problem. Now i have to make all the four networks to communicate with each other. So as you want to know if i enabled packet forwarding in /etc/sysctl.conf file, I did it. i enabled , so next part is configuring iptables. please tell me how to configure. for all the four nic cards. please help me. As if now no lan card is connected directly to internet.

thank you.

If you have 4 networks and wish to route between them, you do not need any masquerading.

Once you have input those commands, your box should be able to route traffic between the various networks. If you are having trouble, make sure that you have set the gateway on your other machines correctly.

If you are still having issues after this, please make a network diagram with your current configuration.

hi SuperJediWombat!,

thank you, ur right it masquerades all the interfaces am i right ? what if i don't want "A" netowrk not communicate with "C" any rule to drop reques from "A" to "C"

thank you.

I thought we already cleared all that up? Just put a REJECT on that route

iptables -A FORWARD -i eth0 -o eth2 -j REJECT

for example