Mail Submission Protocol
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
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.
More information about the NANOG