Sendmail on a LAN

[JD]

  On 08/17/2010 11:12 AM, fred smith wrote:
> On Tue, Aug 17, 2010 at 10:09:55AM -0700, JD wrote:
>>    On 08/17/2010 09:36 AM, Tim wrote:
>>> On Mon, 2010-08-16 at 15:24 -0400, Gregory Woodbury wrote:
>>>> Get a dyndns.com name for your router public ip address and set up at
>>>> dyndns to get mail delivered to that name.
>>> Of course, if your IP changes, then mail is going to get screwed up
>>> during the time it takes for next delivery attempt to go to your new IP
>>> address, instead of the old one.
>>>
>>> Dyndns, and other such things, are useful for giving yourself a hostname
>>> that you can control, to a static IP.  But aren't going to be much good
>>> if you have a dynamic IP.  Private webserving's easy enough with a
>>> varying IP, mail serving's another matter.
>>>
>>>
>> My router's public IP address is static. So that is not a problem.
>> But per other replies on  this list, it sounds like
>> a complicated puzzle to solve.
>> I have a dyndns name. and it maps onto my router's static IP
>> address. But I think at&t is blocking port 25.
>> I will have to talk to them and see if they will open it up.
>> I really need a tutorial on how I can accomplish this when
>> my sendmail machine is on a LAN.
> some years ago, one of those dynamic dns providers (it might have been
> dyndns--I can't really remember with any certainty) offered a non-free
> service where they would reroute smtp traffic for your domain to some
> port other than 25, so you could put your sendmail (or whatever) on some
> non-standard port, the whole point being to foil the gestapo-like rules
> of some ISPs
Well, that would require that sendmail would have to listen
on that alternate port. How is that accomplished?