Re: Mail Submission Protocol

["Raoul Bhatia [IPAX]" <r.bhatia () ipax at>]

On 22.04.2010 13:07, Tony Finch wrote:
> Er, no. TLS-on-connect aka smtps (as opposed to STARTTLS) is only used
> to support Microsoft MUAs that are more than a couple of years old. They
> only supported STARTTLS on port 25 and insisted on using the deprecated
> TLS-on-connect mode on all other ports. This meant they could not
> support standard Message Submission on port 587. Therefore you should
> treat smtps (TLS-on-connect on port 465) as the special Microsoft
> version of RFC 4409 message submission. That is, treat the protocols
> exactly the same wrt authentication, authorization, firewalls, address
> validation, etc.

i recently had the problem that an lotus notes server insisted on
sending emails to one of our clients via port 465. so having mandatory
authentication there actually broke delivery for an exchange sender.

> X-Mailer: Lotus Notes Release 6.5.4 March 27, 2005
> X-MIMETrack: Serialize by Router on smtp2/xxxxx(Release 6.5.4|March 27, 2005) .....

cheers,
raoul