Re: Federated, decentralised communication on the internet (was: domain names, was: hostname)
Greg Wooledge wrote:
> My understanding: the SMTP receiver will use whatever heuristics it
> finds appropriate to avoid receiving spam.
> One heuristic that is commonly used is to reject all messages where
> the HELO doesn't even syntactically qualify as a valid FQDN -- in other
> words, has no dot in it.
> Another heuristic that is commonly used is to perform a DNS query on
> the HELO string, and reject it if it's not a valid FQDN based on DNS.
and as I mentioned in one previous reply since couple of years every one is
implementing DMARC and SPF. In near feature mails that are not signed, will
not be processed/accepted or will score bad and be treated as spam.