Intermittent 'fault' with Squid 1.1.19?

I've just noticed what I think is an intermittent fault, and am still
trying to isolate the conditions under which it happens!

Background: I allow users to check their account on-line at any time.
To do this, I run a CGI that uses information provided by apache to
identify the caller. If they are a static IP, it's easy: their hostname
tells me who they are. If they are a normal dynamic dial-in, I take their
port number, check who's on that port and use that.

Problem: Although this has been working fine for nearly 2 years, I had
four people in the last 48 hours who have got the "wrong" bill. That is,
the correct bill, but not theirs! All the details are for a different
subscriber.

I've extensive logging, and checked each part of the scripts, and
everything leads me back to squid appearing to be supplying the wrong
"forwarded-for" details.

This would be no problem usually, and the only one who would even notice
would be a really attentive person going through the squid logs. In my
case, it's a serious problem. Has anyone else observed anything similar?
Got any suggestions how I can hunt it down? I have not been able to
reproduce it so far, but the 4 people who reported it are well known to
me and are unlikely to be making it up. Apart from which, the logs
confirm the details sent were indeed NOT those for the correct person!

Thanks for any assistance
RossW
Received on Mon May 12 1997 - 15:12:40 MDT