Am 02.04.2011 21:00, schrieb Alex:

>> Fix your client to properly use TLS AND THEN SASL.
> 
> I'm using the K9 client for Android. Using this method with TLS and
> SASL I need port 25 open for SMTP and TLS, and 587 for submission and
> SASL, correct?

i believe you need some clarify

SASL-Auth and TLS/SSL are independent

TLS/SSL is the first step
587 = submission and implicit SASL-Auth, TLS may
25 = SASL may, TLS may
465 = smtps (no TLS handshake, it is SSL per definition)

the point is that TLS happens while connecting
on 25/587 the server OFFERS TLS, but it is not requested
so the first part of the connection is unencrypted
after the client "sees" STARTTLS the SSL handshake can follow or even not

on port 465 there is no "may offer", 465 is dedicated SSL

SASL-Authentication happens AFTER the connection/tls/ssl-handshake
that is why "SASL only after TLS" makes no sense

SASL is used for allow or deny relay
587 (submission) is used only for authenticated clients
25 CAN be used for that, but is blocked by many providers because
it maybe used without Authentication because other mailservers deliver their
messages over port 25 to you and they can not authenticate to a MX
for normal relaying their users mail

that is why 25 form most client-networks is blocked outgoing because
spambots are using port 25 for their crap and if yiu have a account
you should use 587 for submit your messages to your mail-provider

Attachment: signature.asc
Description: OpenPGP digital signature

Reply via email to