Amazon SES – “Illegal Header” errors

Update 8/2/2011: please see the followup post for a possible workaround.

A few people have inquired about the “Illegal header” error when attempting to relay email through SES. “Oncle Tom” pointed to a thread on Amazon’s forums about a similar problem which led to a list of headers Amazon will accept. The list is below; if you need to add headers outside this list, you can do so using “X-Headers.”

Some people have posted sample code in the thread with modifications to ses-send-email.pl to replace “illegal” headers read from STDIN with an equivalent X-Header. I wrote something generic that takes the list of legal headers and replaces anything not on that list with its X-Header equivalent. Disclaimer: I haven’t tested it, but it seems like this type of solution would be more adaptable since you don’t have to keep fixing it every time a new application attempts to send email with a new header. I haven’t worked this into ses-send-email.pl (since I’m not having any problems, I don’t want to touch it 🙂 ) but I fed in an email header and the output looked correct.

https://gist.github.com/1068310.js

Input email:

MIME-Version: 1.0
Received: by 10.142.136.15 with HTTP; Mon, 16 May 2011 09:32:44 -0700 (PDT)
Date: Mon, 16 May 2011 12:32:44 -0400
Delivered-To: evandhoffman@gmail.com
Message-ID: 
Subject: Hi friend.
From: "Evan D. Hoffman" 
To: "Evan D. Hoffman (Personal)" 
Content-Type: text/plain; charset=ISO-8859-1

Email Test.

Output email:

[evan@EvanMBP ~]$ perl replace-headers.pl test-email.txt 
MIME-Version: 1.0
Received: by 10.142.136.15 with HTTP; Mon, 16 May 2011 09:32:44 -0700 (PDT)
Date: Mon, 16 May 2011 12:32:44 -0400
X-Delivered-To: evandhoffman@gmail.com
X-Message-ID: 
Subject: Hi friend.
From: "Evan D. Hoffman" 
To: "Evan D. Hoffman (Personal)" 
Content-Type: text/plain; charset=ISO-8859-1

Email Test.

Hope this helps someone.

Here’s the legal header list, from http://docs.amazonwebservices.com/ses/2010-12-01/DeveloperGuide/index.html?AppendixHeaders.html

• Accept-Language

• Bcc

• Cc

• Comments

• Content-Type

• Content-Transfer-Encoding

• Content-ID

• Content-Description

• Content-Disposition

• Content-Language

• Date

• DKIM-Signature

• DomainKey-Signature

• From

• In-Reply-To

• Keywords

• List-Archive

• List-Help

• List-Id

• List-Owner

• List-Post

• List-Subscribe

• List-Unsubscribe

• Message-Id

• MIME-Version

• Received

• References

• Reply-To

• Return-Path

• Sender

• Subject

• Thread-Index

• Thread-Topic

• To

• User-Agent