Linux Routing Firewall Help please !!

Posted on 2007-04-05
Last Modified: 2013-12-16
I am trying to configure a firewall with 2 nics.

eth0      Link encap:Ethernet  HWaddr 00:15:E9:FA:43:6E
          inet addr:  Bcast:  Mask:
          RX packets:6127 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5583 errors:0 dropped:0 overruns:0 carrier:0
          collisions:44 txqueuelen:100
          RX bytes:3368292 (3.2 Mb)  TX bytes:725801 (708.7 Kb)
          Interrupt:11 Base address:0xd000
eth1      Link encap:Ethernet  HWaddr 00:04:5A:7A:E4:48
          inet addr:  Bcast:  Mask:
          RX packets:3408 errors:0 dropped:0 overruns:0 frame:0
          TX packets:737 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:334099 (326.2 Kb)  TX bytes:53127 (51.8 Kb)
          Interrupt:10 Base address:0x5c00
lo        Link encap:Local Loopback
          inet addr:  Mask:
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:22347 errors:0 dropped:0 overruns:0 frame:0
          TX packets:22347 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1528193 (1.4 Mb)  TX bytes:1528193 (1.4 Mb)

if I disable eth1 then I can access the internet and ping works all the way around. But when I enable eth1 for the internal network I get the following

[root@firewall root]# ping
PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=64 time=0.039 ms
[root@firewall root]# ping
PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=255 time=0.818 ms
[root@firewall root]# ping
PING ( 56(84) bytes of data.
From icmp_seq=1 Destination Host Unreachable
[root@firewall root]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface U     0      0        0 eth0   U     0      0        0 eth1     U     0      0        0 eth1       U     0      0        0 lo         UG    0      0        0 eth1

According to the documentation I have read this set up should work and I am at a loss for what to do next.
Any idea's?  
Question by:MarkWP
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Accepted Solution

cheesygit182 earned 500 total points
ID: 18861271
"inet addr:  Bcast:  Mask:"
That's your problem. Your usage of the kernels routing tables is perfect, but one of the NICs isn't configured correctly. Test them individually and paste the results of ifconfig here, for each.


Author Comment

ID: 18861500
I had a gateway entered on both nics

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