There were even customized ports of Qmail in the past that had options that could be easily be enabled to downright refuse email from emails hosts not matching A/PTR or HELO...not exactly good citizenship....
Cheers On 11 August 2017 at 10:49, Craig Skinner <skin...@britvault.co.uk> wrote: > On Thu, 10 Aug 2017 17:18:45 Stuart Henderson wrote: > > You can't expect to reliably deliver email unless you have a PTR > > record and an A/AAAA record (at least within the same domain, though > > in some cases the full hostname needs to match). > > Yes - matching DNS PTR/A records, and HELO hostname generally seem to be > ranked higher for delivery than the SPF/DMARC/DKIM/etc optional extras. > > Cheers, > -- > Craig Skinner | http://twitter.com/Craig_Skinner | http://linkd.in/yGqkv7 > > -- Regards, -- Rui Ribeiro Senior Linux Architect and Network Administrator ISCTE-IUL https://www.linkedin.com/pub/rui-ribeiro/16/ab8/434
