We actually manually list our customer ranges in pbl, or at least used to. Probably something else that I need to check on. On Fri, Apr 21, 2023, 8:04 AM Lukas Tribus <lukas@ltri.eu> wrote:
Hello,
without PTRs you will probably get your prefixes listed in things like Spamhouse PBL. So adding the correct PTR for a mailserver may not be enough, as services like that love to classify entire IP blocks. Of course Spamhaus provides the tools to fix this issue. But what if there are 4 - 5 other services like that? Do you want to go down that rabbit hole, everytime you turn up a mailserver in your prefix?
I also think reverse DNS records are useful when you have discussions with content providers for all sorts of reasons like geolocation issues or "VPN" classifications.
Of course whois/irr records are the proper tools for this. But if I have to discuss my IP ranges with some first level support desk at a large content provider, everything that stands out negatively will impact my chances of actually getting it done and how fast it will get done.
Considering how subjective IP classifications are, I will not return NXDOMAIN for v4 addresses if there is even a small chance that it will make my life harder at some point in the future.
Lukas