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Old 12-13-2002, 06:14 PM   #1
rita100
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Registered: Dec 2002
Distribution: custom kernel
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not able to ping beyond the firewall


Hello,

This is how my setup looks:


PC -----> Linux------>hub->firewall
eth1 eth0

The PC is connected to the Linux box using a crossover cable. The Linux box has 2 ethernet interfaces. For the application to run on Linux, it is necessary that both the NICs have the same MAC address. Both the NICs have the same IP Address. I am running a Linux 2.4.18 customized kernel, with iptables and divert sockets.

Now, from my PC I am able to ping to machines with the same subnet address. However, I am not able to ping machines beyond the firewall. When I did a tcpdump on eth0, I see the requests going out, but I do not see the replies.

I am able to ping beyond the firewall when I originate the ping from the Linux box.

I would appreciate any help.

Thanks

Rita
 
Old 12-14-2002, 03:36 PM   #2
peter_robb
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I'm not sure why you MUST have equivalent MAC and ip addresses on both NICS...
Packet routing relies on there being individually addressable nics...
 
Old 12-14-2002, 10:58 PM   #3
Ciccio
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is your linux box working as a router adn firewall??? with tcp_forward and iptables/ipchains???? If so make sure you've enabled the ping response.
 
Old 12-16-2002, 05:42 PM   #4
rita100
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Yes, the box is behaving like a firewall and a router. I have enabled iptables and ip_forwarding too.


Last edited by rita100; 12-16-2002 at 05:43 PM.
 
Old 12-16-2002, 06:35 PM   #5
Ciccio
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/proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

and

/proc/sys/net/ipv4/icmp_echo_ignore


should be set to 0 so you can ping the server. (echo "0" > /proc/~
 
Old 12-16-2002, 06:43 PM   #6
DavidPhillips
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sounds very strange,

are you sure ip masquerade won't work
 
Old 12-16-2002, 07:19 PM   #7
Ciccio
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are you nating correctly???
 
  


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