> -----Original Message----- > From: owner-postfix-us...@postfix.org [mailto:owner-postfix- > us...@postfix.org] On Behalf Of Kris Deugau > Sent: Friday, September 09, 2011 6:32 AM > To: postfix-users@postfix.org > Subject: Re: What does Postfix stamp... > > Not to mention, at least in my experience it's the IP that introduced > the message to the Internet (ie, the sending client's IP, or webmail > user's IP), not the IP that connected to your server.
More often than not, that's what people actually want because it identifies who really sent the message, not who last handled it before you got it. But it's unreliable for all kinds of reasons: - it could be forged to indicate it came from a legit source when it didn't - there could be more than one of them, so which one do you believe? - it might be stripped in transit - it's non-standard If its value can't be trusted, you should just ignore it.