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. > >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*. > (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? 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. -- Regards, Jaroslaw Rafa r...@rafa.eu.org -- "In a million years, when kids go to school, they're gonna know: once there was a Hushpuppy, and she lived with her daddy in the Bathtub."
