Problems with incoming Internet traffic since IP change

[innerwitness]

If you can help me on this please do I inherited this part of my job and do not claim to be an expert on microsoft servers.

We have a 2003 SBS R2 standard edition with 2 internet connected NICs one DSL and One cable modem and one inward facing NIC. The Internet NICs use NAT and firewall through Routing and Remote Access for port forwarding.
This configuration has worked for several years now until Comcast changed our static IP on the cable modem as follows.

OLD IPs
DSL: 70.109.94.XXX
CABLE: 24.38.87.150

New IPs
DSL 70.109.94.XXX No Change
Cable: 75.132.80.XXX

Now if the new cable static IP is entered the DSL stops recieving incoming traffic like the NAT quits forwarding. The reverse is also true if the cable NIC is up and the DSL NIC IP is added then the cable connection stops recieving incoming traffic. I saw a Microsoft Knowledge Article(KB907464)
that talks about ICF only opening ports on the most recently IP address, I don't know if that applies here.
Has anyone heard of this before and is there a fix?


Thanks for the help

 

[ShackDaddy]

What are you "adding" the addresses to? The scenario is unclear in that respect.

This is hard to troubleshoot without looking at it. Sounds like there are other settings that you aren't looking at. Are there any static routes in place that you need to change?

Dave Shackelford
MCSE, CCNA, Microsoft MVP: Exchange
Shackelford Consulting

 

[innerwitness]

Dave

Thanks for the reply.

I did not add an IP per say, the cable company here (adelphia) was aquired by Comcast and they are changing all the static IP address. This is a configuration that worked for over 2 years until Comcast forced the IP change.
This is a very simple setup no static routes, only 4 workstations, and a few dozen customers who hit ftp and web sites. It just seems that with certain IP combinations on the two public NICs only one will pass traffic through the firewall.

I was able to take an old Linksys router with NAT and translate the Comcast IP back to the old IP and everything works fine. So I am working for the moment, but I am curious if there are settings I am missing or if Microsoft SBS 2003 has a problem with 2 public NICs.

Thanks again for the reply!!

Nick