Cyrus Daboo wrote:
2) What about outgoing?
Are MX records considered the solution?
Using GMAIL as an example, I think it only allows IMAP for receiving and
SUBMIT (port 587) for sending. So wouldn't a SRV record be useful for
the case where SMTP is used for outgoing when the incoming uses IMAP?
The current spec defines _submission._tcp in Section 3.1 which covers
email client submission server discovery.
Sorry, I missed that section (short section, page cut off).
Ok, so overall, a suggested logic would be:
- Query for _pop3s, _imaps, _pop3, _imap
(order implementation based)
- If more than one, offer user selection.
- Query for _submission
I think this is a simple protocol logic for implementation. Anything
beyond that is specific to the MUA client.
Regarding SRV in general, I can provide some personal experience.
You might consider some of these as "encouragement" material for any
Until sometime in 2008, we used an NT 4.0 domain controller and DNS
server and never had a need to upgrade. The machine served its
isolated purpose. Hotfixes were provided per MS request but that ended
in 2008 and last year's DNS "DoS Exploit of the year" forced the issue
to update the DNS server. The DNS server was moved to a Windows 2003
enterprise box. That move solved the security issue and also allowed
us to use SRV records to improve our jabber (XMPP) server discovery
So I think past reasons for not using SRV are passe. At least within
the legacy windows world, SRV records are more applicable today from a
support standpoint because any remaining DNS 4.0 server can no longer
operate safely and are forced to upgrade thus offering SRV query support.