On 2021-07-05 09:35:22 -0400, Greg Wooledge wrote: [...] > Your "reverse" (PTR record for 162.213.253.79) doesn't match. Which is > to say, none of the "A" results from cyrania.com. match the original > IP address of 162.213.253.79. > > Some SMTP receivers may care about that. [...]
Yes, the reason is that the owner of the IP address can technically put anything for the reverse, in particular a domain he doesn't own. Thus he can put a domain with a good reputation to send spam. That's why antispam software should check that the reverse resolves back to the IP address. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)