ISPs blocking SMTP connections from dynamic IP address space
Louis LeBlanc
freebsd at keyslapper.org
Mon Jun 7 10:51:39 PDT 2004
Wow. Looks like all my other emails are starting to come through. I
don't know why, but it seems email slowed down to snail-mail pace this
weekend. Bill, if you see anything in the headers to my messages that
might seem wrong, and have some idea, I'd be infinitely grateful for
any pointers.
To everyone else, I apologize for the barrage of emails I've sent in
the last few days that is just starting to get to the FreeBSD MX
systems.
Lou
On 06/07/04 01:18 PM, Louis LeBlanc sat at the `puter and typed:
> On 06/07/04 12:36 PM, Bill Moran sat at the `puter and typed:
> > Louis LeBlanc <leblanc at keyslapper.org> wrote:
> >
> > > Bill Moran wrote:
> > > <SNIP>
> > > I think something has changed in this respect lately. I've sent close
> > > to a dozen messages to the FreeBSD list since Saturday, and not one has
> > > gotten through.
> > >
> > > I'm running sendmail on FreeBSD 4.10, and relaying through Verizon's
> > > authenticated SMTP system. The thing is that I am also using Zoneedit
> > > to convince the world that keyslapper.org is at my current IP, and this
> > > is reset every time I get a new IP. This means that when a relay does a
> > > lookup on the message, it sees it is a DHCP (DSL) address, and the
> > > message is stopped - by the FreeBSD list server in many cases.
> >
> > I'm not 100% sure I understand what you're doing, but regardless, I think
> > you're barking up the wrong tree.
>
> I sincerely hope so. If that's the case, I can probably fix it from
> home. My sendmail config (on keyslapper) authenticates to
> outgoing.verizon.net, and sends all mail for keyslapper.org. Since I
> use mutt and keep an IMAP server on keyslapper, I often send mail from
> work for my keyslapper.org accounts. That's why you saw the leblanc
> system in the headers.
>
> > First off, the only DNS info that mx1.freebsd.org checks is the
> > server it's actually talking to. In the case of this last message,
> > that's mail-relay1.mirrorimage.net:
> >
> > Received: from mail-relay1.mirrorimage.net (mail-relay1.mirrorimage.net
> > [209.58.140.11])
> > by mx1.FreeBSD.org (Postfix) with ESMTP id 3D90343D1D
> > for <freebsd-questions at freebsd.org>;
> > Mon, 7 Jun 2004 16:01:45 +0000 (GMT)
> > (envelope-from leblanc at keyslapper.org)
> >
> > Now, if you're sending this route, and having trouble getting
> > messages through, then it's a config problem with the
> > mirrorimage.net folks.
> >
> > However, if you're trying to send directly from this machine:
> >
> > Received: from keyslapper.org (LEBLANC [10.10.4.59]) by
> > triton.int.mirrorimage.net with SMTP (Microsoft Exchange Internet Mail Service
> > Version 5.5.2653.13) id MJT1GA4V; Mon, 7 Jun 2004 12:01:38 -0400
>
> Yes, I mailed this from work, but I'm not sure why the headers did
> this. I'm running postfix on my FreeBSD box there, and I'm still
> using the default. I should set this up to relay directly through our
> SMTP server. I honestly don't know why it went to keyslapper.org at
> all (I mostly work with HTTP server stuff, and am woefully short on
> mail protocol understanding). I sent from leblanc, my FreeBSD machine
> at work, running postfix.
>
> > Then the problem is not that it thinks that you are a dhcp addy, but
> > that your HELO/EHLO announcement is calling the server "LEBLANC",
> > which isn't even a valid DNS name, and therefore fails the lookup
> > check.
>
> I don't understand why it's doing this. Time to read some more docs.
>
> > > I've even sent mail from Netscape, using the Verizon SMTP relay
> > > directly, and the same thing happens. Ditto from work. Just
> > > because leblanc.eng.mirrorimage.net is on a private ip and doesn't
> > > resolve outside doesn't mean it isn't a real legitimate system.
> > > It's pretty annoying. Since Friday afternoon, all email I've sent
> > > to addresses other than hotmail, my employer, and internally, have
> > > been blocked somewhere.
> >
> > Sounds like you need to work something out.
>
> Hopefully your feedback here will be enough to get me in the right
> direction.
>
> > And the fact that you're on a private IP _does_ mean that you're not
> > a real mail server. Per RFC-1918, those addresses are NOT part of
> > the Internet, therefore, there's no reason for any mail server to
> > accept that there's a real server there. The only machine that has
> > to recognize that IP is the NAT gateway that translates that IP into
> > a real one.
>
> I think I understand this, but it implies that I might have been doing
> things 'right' all along - or at least as close to that as I can
> expect without getting a commercial account.
>
> > But, then again, from the last email you sent, this isn't your
> > problem.
>
> Not from that point. That message was sent from Netscape using our
> SMTP relay rather than the localhost postfix. This message is being
> sent from my home system (keyslapper.org) which is a DSL system on a
> dynamic IP. I hope you don't mind I'm copying you (normally I would
> never do this), in case the group doesn't get it. I'm copying myself
> at work as well so I can look at the headers more closely.
>
> It looks like I have 2 mail problems here. One is at work: my default
> postfix config is not appropriate for the way I use it. The other is
> at home. Not entirely sure *what* the cause is there, but through the
> magic of ssh, the flexibility of mutt, and a little luck, this message
> might just provide enough info to figure it out.
>
> Thanks for the feedback.
>
> Lou
> --
> Louis LeBlanc leblanc at keyslapper.org
> Fully Funded Hobbyist, KeySlapper Extrordinaire :)
> http://www.keyslapper.org Ô¿Ô¬
>
> QOTD:
> Some people have one of those days. I've had one of those lives.
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>
--
Louis LeBlanc leblanc at keyslapper.org
Fully Funded Hobbyist, KeySlapper Extrordinaire :)
http://www.keyslapper.org Ô¿Ô¬
clairvoyant, n.:
A person, commonly a woman, who has the power of seeing that
which is invisible to her patron -- namely, that he is a blockhead.
-- Ambrose Bierce, "The Devil's Dictionary"
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