[Mailman-Users] Users complain, they don't receive mails from the list

Tue Jan 26 18:56:46 EST 2016

Hi Guys!

Many thanks for all your help so far!
I managed to configure a valid rDNS record to day and the users from the
blockings ISPs startet to receive mails again!

Now I use the domain lists.rc-worms.de. If I enter that into the tool Mark
mentioned (mxtoolbox.com), everything is stated as fine, except for
"Reverse DNS does not match SMTP Banner".

Could you please try to explain this a bit for me?
I use Postfix as MTA...

Many thanks again,
Sascha.
Am 26.01.2016 3:45 vorm. schrieb "Robert Heller" <heller at deepsoft.com>:

> At Tue, 26 Jan 2016 01:27:24 +0100 Sascha Rissel <mailman at rissel.it>
> wrote:
>
> >
> > Dear Mark and all others,
> >
> > many thanks for your help so far.
> > I am just starting to setup this subdomain, Mark advised me to.
> >
> > One thing regarding the Reverse DNS entry:
> > How can it be necessary, to set up this record? Just imagine a server,
> > where multiple domains are hosted, but the server only has one IP.
> > If the ISPs really require rDNS entries, which suit to the mail
> originating
> > domain, one would always need a 1:1 mapping of IP and domain, preventing
> > multiple domains on a one-IP server, isn't it?
>
> You just need one 'real' canonical domain name, like lists.rc-worms.de,
> and
> have a rDNS PTR to lists.rc-worms.de. It does not really matter if there
> is a
> foo-list at foobar.com hosted there. What is being objected to is the
> name<number>.hosting-provider.tld type of name, as well as things like a
> HELO
> that does not match, and such. It has the look-and-feel of a spammer
> sending
> anonymous E-Mails or E-Mails with forged / spoofed addresses (including
> spoofed HELO's). Also the list server's MTA should be using the
> lists.rc-worms.de name in the HELO. And you probably should also have
> a spf record as well. Everything should 'match': the A record, the rDNS PTR
> record, the HELO name used, the SPF record, etc. That makes everything look
> legit and everything fits together.
>
> >
> > Kind regards,
> > Sascha.
> >
> > 2016-01-26 0:48 GMT+01:00 Mark Sapiro <mark at msapiro.net>:
> >
> > > On 01/25/2016 03:27 PM, Sascha Rissel wrote:
> > > > Hi Mark!
> > > >
> > > >> In simple terms, it claims your mail server is not properly
> configured.
> > > >> I don't know what your Mailman server's domain name is, but it
> appears
> > > >> from the error message that its IP is 62.75.175.182 and that IP has
> an
> > > >> rDNS PTR record to euve51864.serverprofi24.de.
> > > >
> > > > this is all pretty correct.
> > > >
> > > > "euve51864.serverprofi24.de" is the natural name of the vServer, I
> am
> > > > running.
> > > > I don't have a real domain configured, since I mainly just use it for
> > > > mailman.
> > >
> > >
> > > As I indicated in a follow-up post web.de is apparently not allowing
> > > 'generic' domains any more.
> > >
> > >
> > > > I configured all Mailman lists to use something like <list name>@
> > > rc-worms.de,
> > > > where <rc-worms.de> is the www domain of my sports club, whose
> > > > administrator I am.
> > > > For better readability I named and configured all lists this way, to
> use
> > > <
> > > > members at rc-worms.de>, <team1 at rc-worms.de> as exlicity reply-to
> address
> > > and
> > > > so on.
> > > >
> > > > This worked pretty well for years.
> > > > Did it now turn into a problem, that reply-to address and domain ()
> bear
> > > a
> > > > different IP/rDNS result?
> > >
> > >
> > > That is not the problem as far as I can tell. The problem is that the
> > > specific domain you are using for your mail server,
> > > euve51864.serverprofi24.de, is now seen as a 'generic' name and is not
> > > acceptable to web.de.
> > >
> > >
> > > > Is there something you could suggest in this case?
> > > >
> > > > Should I maybe configure a subdomain on my vServer, like <
> > > lists.rc-worms.de>,
> > > > from which the mails will be send from and can bear own DNS config?
> > >
> > >
> > > Yes. lists.rc-worms.de should be good. I would have suggested just
> > > rc-worms.de, but that already has an A record pointing to a different
> > > server.
> > >
> > > The issue you will run into is that while you can configure the MTA to
> > > identify itself as lists.rc-worms.de and you can create the A record
> for
> > > it, you don't control the rDNS PTR record for 62.75.175.182. That's
> > > controlled by intergenia.de. It may be no problem to get them to
> change
> > > it, but it could be a stumbling block. You'll find out when you ask.
> > >
> > > With respect to the underlying issue here, ISPs are getting more and
> > > more fussy about only accepting mail from what they consider to be real
> > > mail servers. Trying to run a mail server with a dynamic IP or an IP
> > > with a 'generic' host name is just not possible if you want reliable
> > > acceptance of your mail.
> > >
> > > --
> > > Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
> > > San Francisco Bay Area, California    better use your sense - B. Dylan
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> --
> Robert Heller             -- 978-544-6933
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