[kwlug-disc] Squid breaks Hotmail?

[Paul Nijjar]

We have a bizarro problem that just started today. We were using a
plain-jane Squid proxy through pfSense. The proxy is transparent to
the end user. We basically only use the Squid proxy to filter out a
handful of "bad" sites -- it probably does not speed up access that
much. 

Last week, people were able to access all non-blocked websites fine.
Today, anybody going through the proxy and accessing their
live.com/hotmail mail through the web interface gets the following
problem: they can sign in and see their list of messages, but they
can't open any of the e-mails. They can click the links but the e-mail
body does not open. 

It looks like the problem is Javascript-related. In IE8 there is a
message that there was an "error on the page", but (as usual) IE8 is
so helpful that it won't tell me what the error is. Firefox 3.0 and
3.5 reported an error that was on line 1 of the page (with the
doctype)? I did not have any other browsers handy to try. 

These pages load fine in other areas of the network. They load fine if
I turn off the squid proxy. A quick visual inspection of the page
sources from working and non-working computers made it seem as if the
pages that were loading were identical. 

I can't play too much until after hours (I managed to break our
network once already trying to figure out this problem), but I am
wondering the following things: 

- Is this type of thing a known problem with transparent proxies in
  general or Squid in particular?

- Is this happening to anybody else who is proxying via squid, or is
  it just us? I suspect the latter but it would be helpful to know if
  others are being affected. 

- Are there places I can look for proxy errors? Other places to look
  for clues? There is a /var/log/squid/ directory but it did not seem 
  to have any errors in it (maybe because pfSense disables squid
  logging by default). 

- Does anybody know how to make IE8 tell me what errors it finds in a
  page? I am sure that this is obvious but I did not find the
  location. 

Gah! I hate computers!

- Paul