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Old 06-29-2004, 12:02 AM   #1
yrraja
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Enabling subnet directed broadcast on Linux Router


I am doing some testing and for that i am using a linux machine as router. My problem is that by default the routers do not forward subnet directed broadcast messages and i want to enable this feature for my testing. So far i am unable to find any command that would enable me to do so..

Can anyone here tell me the command to enable Subnet Directed Broadcasting on my Linux Router or direct me to some source where i can find the related help...

thanx
 
Old 06-29-2004, 01:03 AM   #2
DavidPhillips
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Not really sure what you mean, please explain the problem. Are you firewalling the interface?

A router should probably forward broadcasts to the lan like this..

[david@slacker david]$ ping -b 192.168.1.255
WARNING: pinging broadcast address
PING 192.168.1.255 (192.168.1.255) 56(84) bytes of data.
64 bytes from 192.168.1.2: icmp_seq=0 ttl=64 time=0.173 ms
64 bytes from 192.168.1.101: icmp_seq=0 ttl=64 time=0.423 ms
64 bytes from 192.168.1.100: icmp_seq=0 ttl=64 time=0.724 ms
64 bytes from 192.168.1.1: icmp_seq=0 ttl=64 time=1.35 ms
 
Old 07-01-2004, 12:00 AM   #3
yrraja
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I have two networks A and B connected through a Linux Router. From a machine on network A i send a broadcast Ping request to the network B. In return i get Ping Reply from the Linux Router only and not the machines in Network B.
 
Old 07-01-2004, 12:27 PM   #4
DavidPhillips
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So these are seperate networks on seperate interfaces.

You should look at the box on the other side that is suspected to return the ping. You could check it from the router with tcpdump. It is likely that the ping gets to the other subnet and is actually received and replied to.

I think the reply would be treated as a new connection and dropped. If you had a bridge then there would be no problem with broadcast protocols.
 
  


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