[Mailman-Users] Re: Web Mail Agents Generate "Suspicious Headers"?

[Tom Neff]

As Mike says, look at the Privacy options.  SquirrelMail is exceptionally 
well-behaved (I use it myself and recommend it) so I am surprised to see 
its mails rejected.  However, because it is web based and (in the default 
configuration) runs sendmail to send messages, there is one header you 
might well see:

  X-Authentication-Warning: sample.com: apache set sender to 
yourid at sample.com using -f

and I suppose someone might be filtering for that.