[Info-vax] SMTP server using port 587 outgoing?

[Stephen Hoffman]

You're about the billionth person to discover that trying to run a mail 
server on a dynamic IP and with port blocks in place — that's best 
practices for most ISPs, too, as differentiating a mail server from a 
spam engine isn't obvious — involves shenanigans.  Unfortunately, this 
all involves somewhat more shenanigans on OpenVMS.


On 2014-09-11 20:47:02 +0000, snowshoe said:

> Can anyone tell me the magic words to speak to SMTP to get it to use my 
> ISP's outgoing mail server on port 587 (not port 25, which is blocked)?

Relay through another local box, or subscribe to a mail hop service, or 
switch to another IP stack.

> I don't have a recent version of the White Wall and Google is useless.

That's the submission port.

OpenVMS with TCP/IP Services does not support that, which means you'll 
need to use a mail relay service or mail hop service, or you'll need to 
replace TCP/IP Services with the Process Software IP stack (which 
reportedly supports using the TCP 587 SMTP submission port), or you'll 
need to run Postfix or Lamson Project or some other mail server on 
another box on your local network, and aim the TCP/IP Server SMTP 
server at that.

> It uses SMTP AUTH which means I have to supply the ISP user/password 
> combo as well as an outgoing mail server name/address.

That's not supported by TCP/IP Services.

> Right now, the default is direct to MX on port 25 which is blocked, so 
> no mail gets out.  This is a hobby system.  Thanks in advance.

Mail servers operate on TCP port 25, and are expected to have proper 
DNS.   You won't be able to have proper DNS here.

Mail clients use TCP 587 to communicate with the mail server.

The dynamic DNS providers can offer relay services, though usually at 
an extra cost.

Accepting inbound mail involves setting up DNS or remote hosts can and 
will drop messages to your server — assuming there's not also an 
inbound port block — and if this thread follows the usual arc of these 
discussions, you'll end up using an add-on IMAPSYNC or some other tool 
to haul the messages over from your remote server onto your VMS server, 
dealing with the inherent DNS-level misconfigurations that will get the 
server detected as a problem server or spam engine by other mail server 
(due to the inherently invalid DNS, if you're not also in a blocklist 
due to your IP address) and, well, this whole pile of hackery gets 
unstable and flaky and generally messy because you're not supposed to 
be running a mail server on a dynamic IP account.



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