{"id":5284,"date":"2021-09-09T11:57:15","date_gmt":"2021-09-09T11:57:15","guid":{"rendered":"https:\/\/pariswells.com\/blog\/?p=5284"},"modified":"2021-09-09T11:57:15","modified_gmt":"2021-09-09T11:57:15","slug":"resent-from-header-rewrite-envelope-365","status":"publish","type":"post","link":"https:\/\/pariswells.com\/blog\/research\/resent-from-header-rewrite-envelope-365","title":{"rendered":"Resent-from Header \\ ReWrite \\ Envelope – 365"},"content":{"rendered":"

Sender -> Forward Server -> Reciepient<\/p>

Exchange 2010 uses a Resent-From<\/strong> header that is added to the message while it is being forwarded externally by the forward server ( this address is the email account used to forward the email )\u00a0 so emails to the Reciepient server, are checked for SPF check using the Resent-From address and IPs. Which Pass!<\/p>

With 2016 or Office 365 this Resent-From header is not there and the external contact server does the SPF check using the original sender’s domain and forward server IP address and it hard fails spf.<\/p>

Workaround: Message Header ReWrite<\/p>

Use Mimecast to Rewrite the Envelop from Address to the Resent-From\u00a0<\/strong>Address instead<\/p>

Configuring Address Alteration Definitions and Policies (mimecast.com)<\/a><\/p>

 <\/p>

SRS Should be doing this as well<\/p>

Sender Rewriting Scheme (SRS) in Office 365 – Office 365 | Microsoft Docs<\/a><\/p>","protected":false},"excerpt":{"rendered":"

Sender -> Forward Server -> ReciepientExchange 2010 uses a Resent-From header that is added to the message while it is being forwarded externally by the forward server […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3569],"class_list":["post-5284","post","type-post","status-publish","format-standard","hentry","category-research","tag-resent-from"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t