Mail Submission Protocol
Dave CROCKER
dhc2 at dcrocker.net
Wed Apr 21 22:17:28 UTC 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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