Getting around ISP SMTP firewall settings (Re: Submitting a new port if send-pr is broken)

Ted Mittelstaedt tedm at
Mon Nov 26 21:23:04 PST 2007

> -----Original Message-----
> From: owner-freebsd-questions at
> [mailto:owner-freebsd-questions at]On Behalf Of Bob Richards
> Sent: Monday, November 26, 2007 3:45 AM
> To: freebsd-questions at
> Subject: Re: Getting around ISP SMTP firewall settings (Re: Submitting a
> new port if send-pr is broken)
> On Mon, 26 Nov 2007 13:15:59 +0200
> Giorgos Keramidas <keramida at> wrote:
> > 
> > I don't think there's an easy way to set up the local Sendmail
> > installation to *receive* email from the world without some sort of
> > `static address' though. 
> Actually there is an easy way, I do it here at my work station which is
> on a boat, and uses many different modes of connectivity. All of which
> are floating IPs.
> Get a domain name at dyndns. (it's free) 
> You can also DNS any domain you own for about $29.00/Year, and simply
> MX your mail to your dynamic domain machine on a variety of alternative
> ports.

To be perfectly clear this isn't really receiving mail.  Your configuring
a system at or some other mail forwarder to receive your
mail for you then forward it on to your system using the alternative

You can just as easily set up a mailbox on the dydns server (or
whoever will sell you a mailbox - tons of ISPs will do it) and
fetchmail your mail via POP3 from it.

> Install ddclient on your machine; it will keep your IP updated at
> dyndns.
> Install an mta, like sendmail, and smart-host it to your ISP; or
> smart-host it to dyndns if your ISP can't/won't do it.
> I have been doing this for about 2 years now, and have had no problems
> at all.

I'm sure you don't because in effect your doing exactly the same thing
that any typical e-mail client does - your offloading the heavy lifting
of receiving mail - the spam and antivirus filtering - to a real mailserver
somewhere on the Internet.

Frankly, unless you processing mail for a lot of people, there is no
benefit to running your own mailserver, and you really ought to be
using a client-server model for getting mail, as you are doing.  The
OP just hasn't realized this yet.


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