I have UTM as a spam/virus filter in front of my email server.
Inbound SMTP (port 25) is only ever going to be "anonymous" SMTP delivering to my email server, or relaying from static IP addresses.
I frequently see authentication fails along the lines of
server_login authenticator failed for (USER) [145.249.107.135]:37894: 535 Incorrect authentication data (set_id=username@domain.com)
As I do not allow authenticated SMTP inbound, is there a method of auto banning or blocking IP addreses that attempt to authenticate on SMTP ?
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