DMZ and Linux

You need the following to have a working computer in the DMZ:

- valid IP address that is part of the address range of the DMZ
- Default gateway on the machine set to the external router
- static route on the machine pointing to your LAN address range, specifying the firewall as the default gateway (or else having a static route to your LAN on the external router being used as a gateway)
- Carefully go through /etc/inetd.conf and turn off services which should not be open. This might include response to icmp messages.

To test connectivity, use the traceroute command along with the ping command. Test the following, and make sure all work:

- to the external router's internal IP address (the DMZ side). Should be 1 hop.
- to the external router's external IP address (the internet side) by number. Should be 1 or two hops, depending on router. If you can't get here, check the router. (The router might be blocking ICMP).
- To your DNS server by number (if you cannot ping or traceroute here, not much else will work)
- To somewhere else on the net
- To some address by number on your LAN (inside the firewall). Note that if your firewall is doing NAT, you cannot do this.

If you can ping somewhere by IP number and not by name, check you DNS entries (linuxconf tool or /etc/resolv.conf)

Good luck