Mail Submission Protocol

Dave CROCKER dhc2 at dcrocker.net
Wed Apr 21 17:17:28 CDT 2010



On 4/21/2010 6:49 AM, Claudio Lapidus wrote:
> So we are considering ways to further filter this traffic. We are evaluating
> implementation of MSA through port 587.


RFC 5068, Email Submission Operations: Access and Accountability Requirements, 
is a BCP.  It specifies authenticated port 587 for email submission across the 
net.

As others have noted, it works well through a wide variety of access 
environments.  I don't remember the last time I found it blocked.  I use it over 
TLS, of course.

Blocking of outbound port 25 for all hosts not explicitly authorized has become 
common.  The fact that 587 default to authenticated is the win.

d/
-- 

   Dave Crocker
   Brandenburg InternetWorking
   bbiw.net




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