> On 21 Sep 2016, at 01:40, Sebastian Nielsen <sebast...@sebbe.eu> wrote: > > I would really suggest using DISCARD instead of "500 This TLD sends spam - g > e t lost.". > Thus the spammer dosen't get to know he got stuck in a spam filter and can > update their tools to bypass it.
Spammers generally don’t pay that level of attention to SMTP responses, far less fine-tune their address lists and tools. These morons just find a victim host or botnet to blast out crap to a bazillion email addresses, not caring if any of them work or not or if their spam makes it as far as getting presented to a human victim. Then move on to the next victim host/botnet and repeat with the same list of a bazillion email addresses. Or an even bigger list. Once the spam generating software’s fingerprints eventually get spotted by SpamAssassin or whatever, a spammer will just throw that generator away and either tweak it a little or get a new one. Repeat. FWIW I see the same bogus recipient email addresses (which never existed) repeatedly showing up in most of the spam attempts which arrive here. Clearly, those addresses are being swapped/traded by spammers or I have one very persistent spammer who only uses the same addresses over and over again. Either way, they don’t care that RCPT TO fails because they’re trying to deliver to email addresses that have never existed. If spammers did as you seem to think, these addresses would have been deleted from their lists a long time ago. They haven’t. > DISCARD accepts the mail but throws it into /dev/null True. But it means the spammmer still gets to burn your bandwidth and your CPU cycles as they deliver crap to your /dev/null. That does not seem sensible to me. YMMV. Saying "500 This TLD sends spam - get lost” usually kills the SMTP session *well before* the DATA part of the handshake. So you don’t receive the spam payload. The message doesn’t get to your server. You also get the satisfaction of saying something rude back at the scumbag that was sending spam. Which eases the blood pressure even if it has no impact on that scumbag. You’ve made your choices. I’ve made mine. We’re both happy with the ones we made.
