Let me start off with some environment details. Our fax server is Windows 2003 and I am using the Microsoft Fax Service. I have two modems installed on this server, both of which are U.S. Robotics, one is an older 33.6K while the other is a brand new 56K. The 33.6 is attached to the server via serial and the 56 is attached via a serial to USB connector (not ideal I know, but it's what I have to work with).
Anyways, we receive ~50-75 faxes a day through this fax server and don't seem to have a lot of issues with it since standing it up about 2-3 months ago. However, intermittently I receive complaints from outside offices that are faxing to us that they are getting fax received confirmations on their end, but we are not receiving the faxes on our end. Basically a large number are able to fax to us and only a small percentage aren't.
Troubleshooting done so far includes checking the log files in C:\Docs&Settings\All Users\Application Data\Microsoft\Windows NT\MSFax to try to determine the issue, but any information regarding received faxes that failed don't seem to include the sender's fax number. I have also lowered the port speed from 11520 to 9600 and turned off compression.
I am at a loss now for where to go, is it the outside office's issue or mine?
