ISPs blocking SMTP connections from dynamic IP address space
leblanc at keyslapper.org
Mon Jun 7 09:01:46 PDT 2004
Bill Moran wrote:
> "Lucas Holt" <Luke at FoolishGames.com> wrote:
>>Just make sure they are truly dynamic ips. Many people block ips identified
>>as "DSL" connections. Those are not necessarily dynamic ip based.
> It's wonderful that most ISPs haven't figured out how to play nicely with the
> rest of the world. I only block when I can verify that it IS a dhcp addy.
> There are also blocklists that specifically list verified dynamic IPs.
> It would be nice if all ISPs could agree on a convention that could be used to
> identify these machines. Such as using <uniquename>.dhcp.<domainname> so it
> could be easily filtered.
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
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'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
If this email makes it to the list, it will be the first in awhile.
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