Today at work we had a complaint that one of our remote offices couldn't make a new job posting to Monster.com. Many of our offices have transparent squid implemented, and this is one of them.
Then error that the user would see was:
The following error was encountered: The request or reply is too large.
According to a few places, the problem potentially lied with the reply_body_max_size setting. However, in most recent versions of Squid, this is set to unlimited by default. After some poking around in the Squid docs, I noticed that upping the reply_header_max_size setting from the default of 20 KB to 40 KB seems to resolve the issue. The applicable setting is:
reply_header_max_size 40 KB
If this setting does not work for you, try upping the request_header_max_size as well, which would cause failure for similar reasons. Good luck!