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I have an UBUNTU server VM installation with two NICs. eth0 is on the LAN network, configured by DHCP and is working fine. I manually configured eth1 with a static IP on the DMZ network but can't ping it, I think this might be a routing issue but I'm new to this so any help would be appreciated! Please see below for 'ifconfig eth1' and 'route -n':

Destination    Gateway      Genmask        Flags  Metric  Ref  Use  Iface        UG     100     0    0    eth1  U      0       0    0    eth0  U      0       0    0    eth1


Link encap:Ethernet  HWaddr 00:50:56:ae:00:08
inet addr:  Bcasr: Mask:
inet6 addr : fe80::250:56ff:feae:8/64 Scope:Link
RX packets: 23 errors:0 dropped:0 overruns:0 frame:0
TX Packets:22  errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txquwuwlwn:1000
RX bytes:2306 (2.3 KB) TX bytes:1794 (1.7KB)

Thanks, Charlotte.

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Where are you pinging from? Or you can't ping it from the local machine? – Mr Shunz May 9 '12 at 13:36
I can ping from the local machine, but not from another machine on the LAN. – Charlotte May 9 '12 at 14:33

1 Answer 1

Based on the answer to my comment above...

You should let know to the other machines on the LAN how to reach the subnet.

You said that the LAN address is assigned by DHCP. So I suppose this server is not your default gateway for the LAN.

First, you should reconfigure it as a static address (say, then:

  • Put a route for via (the static LAN IP) on the default gateway of your LAN.
  • Enable ip forwarding on your server, by issueing the command:

    sysctl -w net.ipv4.ip_forward=1

Note: to permanently enable ip forwarding edit the file /etc/sysctl.conf and make sure it has the line net.ipv4.ip_forward = 1. On my ubuntu machine there's something like:

# Uncomment the next line to enable packet forwarding for IPv4
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