Sophos Data Control Rule 552 5.6.0 Headers too large (32768 max)

Question

Hello, 
 
 we have a problem that some Mails could not delivered to some recipients dut to a large Header. 
 
 Error received 552 5.6.0 Headers too large (32768 max) 
 
 The Mails are sent via Office 365 over Transport Rules. 
 
 I would like to reduce the Header via a Data Control Rule, but i'am not quiet sure how to setup the Rule. 
 
 I would like to create a rule which is editing header value, but not sure what to enter in value and header attribut. 
 Any suggestions? 
 
 Thank you

Stuart James · Answer

Your headers aren&rsquo;t the problem. No header will ever get to 32mb. You must have attachments to make it report an error like that. A 32mb email is quite big. 
 
 This is about user education. In my view, the sender should be using OneDrive to share files, not email. Otherwise your mailboxes will fill up way too quickly. Email should be for messages, not file transfers. However, if you wanted to allow this you simply need to increase the maximum email size is office 365 to 50mb, or whatever you need. 
 
 This link may help: community.sophos.com/.../data-control-inspect-modify-header

neha kakar · Answer

Hey hi, you can create a rule to strip unnecessary headers or reduce their size. In the rule, specify the header attribute as content-type and the value as a smaller size, such as text/plain instead of multipart/mixed.

Sophos Data Control Rule 552 5.6.0 Headers too large (32768 max)

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