Very slow SMTP respons even in LAN


New Member
Apr 12, 2023
it takes about 10-15 seconds for the smtp banner to appear.
Also even on the local network when I run telnet on port 25.


Eidt: It was slow DNS server
Last edited:
Eidt: It was slow DNS server
This can be a reason - postscreen probably does quite a few lookups (at least the reverse-lookup for the IP connecting to it. and for all dnsbl's you've configured) - also many smtp-servers and anti-spam solutions do implement quite long pauses before responding (SMTP timeouts are usually configured in the minutes not seconds), as this makes sending spam more expensive for the attackers (smtp tarpitting)

I wouldn't worry too much about this.


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