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Could you please elaborate on the "..., and have a fake first MX record" ?
by born2discover 4y ago
Could you please elaborate on the "..., and have a fake first MX record" ?
- pferde 4y agoLegitimate SMTP servers will try your domain's MX records one by one, in order of priority, until they reach one that accepts the message. Spammers' scripts usually don't bother, they just try the first one and move on to the next address on their list. Of course, this is not 100% reliable, as it's not too difficult for spammers to adapt and improve their scripts. Of course, vast majority of spammers are either not sophisticated enough, or do not care enough to do so, so if you don't mind your incoming mail to be slightly delayed, it's kind of a low-hanging fruit, as it cuts off a huge amount of low-effort spammers.
- acatton 4y agoNot GP, but I think what they meant is having a MX record with a higher priority pointing to an unroutable IP blackhole IN A 240.0.0.1 @ MX 10 blackhole.example.com @ MX 20 mail.example.com
- jhugo 4y agoYup, exactly, for the reasons described in the sibling comment to yours. Doing it this way doesn't even delay mail much most of the time; many legitimate MTAs connect immediately to the priority-20 MX after failing to connect to the priority-10 one.