Re: Spammer succeeded in relaying through my server

[Samer Afach]

Got it. So HELO/EHLO is specifically for MTAs. Thank you very much for explaining! All the best, Sam On 23/12/2022 6:37 AM, Wietse Venema wrote: Samer Afach: Thank you very much, Raf. I really appreciate your empathy and all this help. I'm reading more and more every day. I really appreciate your support. The challenge is knowing what matters. And about your HELO definition, thanks for explaining it. What confuses me is that clients usually don't have hostnames (like my laptop with its Thunderbird installation or my smartphone, don't have a hostname or FQDN to say HELO with), hence making it a requirement is what I don't That is OK, MUAs (mail user agents that connect to port 587 etc) use SASL or some other form of authentication. On the other hand, MTAs (mail transfer agents that connect to port 25) better have a proper hostname, or the odds that their mail will be seen as spam will be high. Wietse