AT&T DKIM Servers - Digital Signature Information & Support

AT&T Postmaster Website

DKIM Servers

When AT&T customers authenticate and send email messages through Yahoo! or other servers, a digital (DKIM) signature is added to the message to associate it with an AT&T domain.

Authenticated messages sent through Yahoo! servers will contain "s=s1024" in the DKIM signature, while those sent by our customers through AT&T servers will contain "s=dkim01."

All authenticated messages will contain a "d=" value in the DKIM signature for one of the following domains:

  • ameritech.net
  • att.net
  • bellsouth.net
  • flash.net
  • nvbell.net
  • pacbell.net
  • prodigy.net
  • sbcglobal.net
  • snet.net
  • swbell.net
  • wans.net