T-Online isn't the only one that wants to see a website associated with
the domain in the PTR record, frankly others do that as well, and best
practices say that website should have contact information available.
I don't think that is unreasonable ask, especially if traffic from that
location triggers or trips a 'suspicious' flag.
In Gmails' case, they as for a SPF record.. everyone can ask for
whatever evidence they need to suggest that a responsible party is
behind the operation of that mail server..
And given our experience in email threat analysis, (you want a couple
thousand examples of throwaway domains being stood up to send spam
without an associated URL every day?) we also strongly recommend that as
a Best Practice if you want to run an email server, that you do this as
well. Was trying to find that M3AAWG document that also suggested that.
Not to say that there aren't some professional spammers who already
throw up a fake accompanying website with fake contact information, so
it isnt' a perfect solution, but I can understand if they want to vet
traffic from a mail server, using that technique makes a lot of sense.
(And of course the spammers that forge someone else's domain in their
PTR records)
Worst case of course, there are some ESP's that don't do this simple
Best Practice, so hopefully T-Online applies the same principles to them
as well.
If you can't put up an associated webpage or redirect the URL to your
company website, well.. frankly the confidence level in your ability to
prevent abuse to our customers from your server drops considerably.
IMHO..
Now I really do have to do, there is this guy with a Gmail account who
says he has $2.3M waiting for me..
On 2022-10-21 10:03, Zack Aab via mailop wrote:
Just to throw my experience in the ring in case it's helpful to anyone:
I had a sender deliver just fine to T-Online until a couple of weeks ago
when they were blocked for (what I determined after conversation with
tosa@) not having a website with contact info available at the outbound
mta's parent domain name (ehlo outbound._mtaparentname_.com). Once a
website redirect was put up they unblocked. I'm guessing it's some
combination of automated crawling for contact info and manually
unblocking the false negatives as they come up (as people who monitor
their bounces reach out).
Just my $0.02.
*Zack Aab* (He/him)
Consultant, Packaged Technology Operations, Shift Paradigm
*O* +1 (512) 717-4097 <tel:+15127174097> | *C* +1 (404) 317-6729
<tel:+14043176729> | *W* shiftparadigm.com <https://www.shiftparadigm.com/>
On Fri, Oct 21, 2022 at 12:52 PM Grant Taylor via mailop
<mailop@mailop.org <mailto:mailop@mailop.org>> wrote:
On 10/21/22 10:30 AM, Laura Atkins via mailop wrote:
> I know a number of mailservers that are able to successfully send
mail
> to t-online.de <http://t-online.de> and have never contacted the
tosa@ address.
I wonder if that hints at a thus-far un-discussed aspect of T-Online's
policy.
There is every chance that T-Online did some sort of analysis of email
traffic to identify likely legitimate senders and primed their white
list with those domains / IPs. E.g. ratio of outgoing messages to
domains / IPs verses spam complaints therefrom.
Similarly, I suspect that T-Online also primed their white list with
the
email oligarchies. -- If I can borrow / re-use what I consider to be
an apt description.
After all, every single list has to start from something. Good lists
organically grow (and shrink) over time as needed.
--
Grant. . . .
unix || die
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