On Fri, Feb 17, 2017 at 06:11:44PM -0500, Viktor Dukhovni wrote: > > > On Feb 17, 2017, at 5:33 PM, Chris Green <c...@isbd.net> wrote: > > > > OK, so the older version is using SMTP STARTTLS which runs on port 587 > > This is how TLS has worked in MTA-to-MTA SMTP for the last > 15 years. > > https://tools.ietf.org/html/rfc3207 > > > and the newer (>=3) version is using TLS directly on port 465. > > No, Postfix 3.0 and later *also* support SMTP over TLS as used > by some systems on port 465. The submission service on 587 and > the relay service on port 25 continue to support STARTTLS. > > To use submission on port 587 the server needs to provide that > service. If a server only supports "smtps" on 465, then that's > what you need to use. > The older (2.9.6) and newer (3.1.0) postfix versions that I'm using are connecting to the same smarthost. I don't seem to be able to connect from the 3.1.0 version to the submission service on 587 for some reason. Do I have to explicitly say I want to use STARTTLS as well as connecting to port 587?
The 3.1.0 configuration is currently:- smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination myhostname = esprimo.zbmc.eu alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases myorigin = zbmc.eu mydestination = zbmc.eu esprimo.zbmc.eu, esprimo, chris.zbmc.eu relayhost = [mail3.gridhost.co.uk]:465 mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 mailbox_size_limit = 0 recipient_delimiter = + inet_interfaces = all inet_protocols = ipv4 smtp_sasl_auth_enable = yes smtp_tls_wrappermode = yes smtp_tls_security_level = encrypt smtp_sasl_tls_security_options = noanonymous smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd message_size_limit = 120480000 compatibility_level = 2 What do I need to change to connect successfully to 587? The 2.9.6 ones already connect successfully to [mail3.gridhost.co.uk]:587 so it is possible. Is it that 'smtp_tls_wrappermode = yes' that I need to remove? I can see little other difference between the configurations. Thanks for all the help/explanations so far, I'm really not very good at all this! -- Chris Green