Address selection from multiple IPs on one NIC

[cbass32]

We have a server that requires two IP addresses (on the same subnet), and both are bound to a singular NIC. All data sent to and from this server flows through a firewall.

Let's say that this server is configured with 192.168.1.10 and 192.168.1.20. If a host connects to 192.168.1.10, it appears as though Windows 2000 randomizes its reply address and will often use 192.168.1.20 as its source address in the reply. Not a huge deal in an unmonitored environment, but it is a problem with the firewall, as its stateful inspection breaks immediately since the reply address isn't as expected.

Does anybody have a solution that forces the server to always reply with the address it has received the traffic on? I know we can relax the rulesets on the firewall, but this isn't the direction we'd prefer to go.

Thanks!

 

[mattjurado]

Just out of curiousity, what is the reason for this configuration? Might be a workaround, but 2000 does weird things with multiple ips bound to the same interface.

Matt J.

Please always take the time to backup any and all data before performing any actions suggested for ANY problem, regardless of how minor a change it might seem. Also test the backup to make sure it is intact.

 

[cbass32]

I'd like to collapse this into 1 address Matt, but it's just not possible because of a DNS/e-mail requirement deal that we have going on. Microsoft does have a method (regedit on a key) for not randomizing reply addresses in Windows 98, but I could not find the relevant information for Windows 2000.

 

[mattjurado]

Have a look at these, I don't have time to read them right now, but perhaps they will reveal registry info that you need.

http://support.microsoft.com/default.aspx?scid=kb;EN-US;131736

http://support.microsoft.com/default.aspx?scid=kb;EN-US;120642

Matt J.

Please always take the time to backup any and all data before performing any actions suggested for ANY problem, regardless of how minor a change it might seem. Also test the backup to make sure it is intact.

 

[cbass32]

Thanks for the link. 120642 does mention disabling randomizing, but it is only for NetBIOS over TCP. We already have this disabled, and need it for any TCP activity. Maybe it's possible that what I'm looking for cannot be done??

 

[mattjurado]

If nobody else has any suggestions, this may be worth a support call to Microsoft. I've called them once in the past 5 years, I suspect it should still be about a hundred bucks or so? If they have a solution, it is probably worth it to you. I'll keep googling, but those links looked to be the only ones containing anything relevant.



Matt J.

Please always take the time to backup any and all data before performing any actions suggested for ANY problem, regardless of how minor a change it might seem. Also test the backup to make sure it is intact.