Evan Hoffman

Amazon SES - "Illegal Header" errors

· 2 min read

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.

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: [email protected]
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: [email protected]
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