Sending Emails: Changing "From" Field Bad?

Just wondering if changing the "From" field when sending email (programatically) is considered a "bad" thing, and will mail servers more likely reject emails sent from my web/mail server because of it (or be marked as spam).

I have a facility where users from my website send emails using a web-interface, so the web/mail server must send the email and change the From field to pretend it's from the user's email.

The RFC doesn't really state much: http://www.faqs.org/rfcs/rfc2822.html

Cheers, SM

edi开发者_JAVA百科t: here are the headers in gmail when I send an email using my web-interface:

Received-SPF: fail (google.com: domain of web_email_addy@mailinator.com does not designate xxx as permitted sender) client-ip=xxx; Authentication-Results: mx.google.com; spf=hardfail (google.com: domain of web_email_addy@mailinator.com does not designate xxx as permitted sender) smtp.mail=web_email_addy@mailinator.com Received: from localhost (webserver.name [yyy]) by sending.domain (Postfix) with ESMTP id 903201474F for ; Fri, 27 Nov 2009 09:10:29 +1100 (EST)

edit2: spf = fail seems bad, but gmail does nothing about it:

http://www.openspf.org/SPF_Received_Header

When an SPF query returns "fail", the MTA should reject the connection.

When an SPF query returns any other result, the MTA should add an advisory header to the message of the form "Received-SPF: neutral" or "Received-SPF: pass". That way, a spam filter further down the road can take that header into account as part of a more balanced decision.

Read about SPF: http://www.openspf.org/Introduction y http://en.wikipedia.org/wiki/Sender_Policy_Framework

It's acceptable really, depending on what you are doing it for. SPF has it's issues though, hence the reason it's not completely used to determine spam.

You may wish you change the "from" address to some non-existent address like "no-reply@" ..., etc.

While you may update the From field, a lot of mail servers tag or mark emails as spam or delete them all together if the from field doesnt match the domain of the origin mail server.