Op 12-04-22 om 14:20 schreef Jaroslaw Rafa:
Dnia 12.04.2022 o godz. 14:07:13 Richard Rasker pisze:
But according to the information supplied, I should also be able to
use smtp.xs4all.nl as a relay host, see
https://www.xs4all.nl/eigenmailserver/ (in Dutch -- and I already
took care of the Spamhaus delisting).
Question: does this solve the PTR record problem?
Probably not, because smtp.xs4all.nl has IP address 195.121.65.191, and
reverse DNS for 195.121.65.191 is 195-121-65-191.dc.kpn.net. So it is also a
"generic" hostname which may cause some systems to reject mail sent from
this address. The ISP has configured it wrong; 195.121.65.191 should resolve
back to smtp.xs4all.nl.
Yes, I figured as much already ... Bit of a shame, really, because
originally, XS4All used to be one of the very best ISP's worldwide, in
regard to both technology as well as customer choice and customer
service -- and I happily paid their rather steep subscription fees in
order to have full control over what I could and couldn't do with my
Internet connection.
After being taken over by KPN, all this seems to have gone down the
drain, with only the high cost remaining. Apparently, this ISP doesn't
want any 'difficult' customers doing things such as running their own
servers and the likes.
For sending e-mail, you don't need to change the MX record.
And how does reverse DNS work in this case?
There is no reverse DNS issue for sending mail. Usually nobody is checking
reverse DNS for the hosts they send mail *to*.
Reverse DNS is checked in case of hosts one receives mail *from*.
Sorry, I wasn't being clear here. What I mean to ask is if (and how)
using a mail relay for sending mail could solve the problem that at the
receiving end, reverse DNS does not match the originating domain.
(And unfortunately, switching to freedom.nl as a new ISP has one
drawback wrt. VOIP -- I can only keep one of our current two phone
lines.)
Why is this? Is your ISP also your VoIP provider?
Yes (although this is way off-topic here). ISP's here offer a package
deal with Internet, TV, and at least one phone line for what used to be
a 'land line'.
I use a VoIP provider that is independent from my ISP and I have set up two
phone lines in my VoIP router. For one line, SIP is listening on port 5060,
and for the other on port 5061. Both lines register with their appropriate
credentials to VoIP provider's SIP server (my VoIP provider is using
separate login & password for each phone line). This setup will work for
any ISP as long as ISP isn't blocking inbound UDP ports 5060/5061.
Perhaps I could do something like that, but then I'd have to spend more
time on that as well. The whole point is that I had everything working
perfectly fine, but that my current ISP demolished essential
functionality without offering any solutions or alternatives.
So I'm still trying to figure out what my best option is -- and a better
understanding of the whole mail server/relay thing is important, which
is why I'm asking here :-)
