SMTP on port other than 25 through DNS???

[Barry Margolin]

In article <9359ki$1cm at pub3.rc.vix.com>, count0 <tim at timmy.ws> wrote:
>
>
>>I get an IP address through dhcp from roadrunner
>>(cable access).  I also have a second-level domain
>>name resolving to this address through dynamic DNS
>>(nameservers at easydns.com).
>>
>>Problem is that roadrunner blocks port 25 so I
>>can't get any incoming mail. 
>
>I though incoming mail was on port 110 (POP3) or IMAP (not sure which
>port) SMTP on port 25 is for sending mail

He means someone sending mail to his machine using SMTP.

>
>> I was wondering if I
>>might be able to alter the MX record in the
>>nameserver to specify an alternative port in
>>addition to my hostname, and then I could have my
>>MTA listening in on that port.

No, there's currently no way to tell all the other mail servers in the
world that you're using a nonstandard port for SMTP service.  This might be
doable in the future with SRV records, but mail systems don't currently
look at them (and since MX records do just about everything that SRV
records do except specifying alternate ports, there's a good chance this
will never change).

>I don't know if it's a DNS issue or not; a mail server is a mail
>server, just configure it to listen on a different port and configure
>your mail client to do the same. (I think....I could be wrong, though,
>anyone can correct me if I am!!) 

He's talking about mail coming from remote mail servers to his machine, not
reading mail.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
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