ip address conflict 1

[heminez]

OK Here goes, My web server keeps giving me an error message saying "the system has detected an ip address conflict with another device on the network having a hardware address of (the address). The hardware address referenced is the inside ethernet port of my PIX firewall. The ip address reported is assigned to the NIC in the server (of course) and IS NOT the same as the IP of the PIX interface. I have check and double checked everything. I even changed the ip address of the web server but the error message resurfaced giving the new ip as the conflicting source. This cropped up on it's own out of the clear blue. No changes had been made to any hardware, software or network topology prior to this happening. I'm at a complete loss on this one! any ideas?

 

[yizhar]

HI.

This is because you are probably using the "ALIAS" command at the pix, and you have not disabled proxy arp.

Solution 1:
Remove the "alias" command from the pix configuration, then "clear xlate" or simply "reload".

Solution 2:
sysopt noproxyarp inside

I would prefer solution 1. Instead of using "alias" to play with DNS, you can sipmly use internal DNS server with private IP address of your web site.

Bye


Yizhar Hurwitz

http://teachers.sivan.co.il/yizhar

 

[heminez]

Your right, I do have the "ALIAS" command in the config. One question though, before removing that line. Is this going to affect the public availability of the web server from the internet? I assume you are saying that my internal DNS servers will resolve the external request coming through the firewall.

 

[themut]

The alias command is used to access servers using the public IP address from the internal network, it does not affect traffic comming from the Internet. If you remove it you will have to access your servers using the private IP address instead of the public IP address. That means you will have to reconfigure your internal DNS server to map the pirvate IP address for your public servers. Your external DNS server should map the public servers to their corresponding public IP addresses just as they are at the moment so it does not affect Internet users accessing your servers.

 

[heminez]

OK Thanks a lot, I did not fully understand what the alias command did. I think that may solve another problem as well. Thanks again