On 14/5/23 09:14, Daniel L. Miller via dovecot wrote:
May 12 15:45:58 cloud1 dovecot: doveadm(194.165.16.78): Error: doveadm client not compatible with this server (mixed old and new binaries?) May 13 03:44:31 cloud1 dovecot: doveadm(45.227.254.48): Error: doveadm client not compatible with this server (mixed old and new binaries?)
Since I don't recognize those IPs, the first is out of Panama and the other is Belize, I assume these are hostile attackers trying to exploit something. How can I defend against this?
Set up a firewall rule that only allows access from an IP range you control. For any other source, simply drop the connection.
You can get really fancy and use port forwarding using ssh to connect from remote but appear as localhost to the server. This access can be configured in dovecot as well as firewall
Jeremy