In message <0ckoi39u8ei1fehs6mlgos1hpvrtfnf45g@4ax.com>, Peter
<occassionally-confused@nospam.co.uk> writes
IP addresses, if they are mobile, make them VPN in to the router before
they can connect to the mail server. Alternatively, out source your
email to someone who can cope and has the tech knowledge to handle
attacks (not deriding your knowledge at all, it can be a real PITA
dealing with this sort of thing)

--
Clint Sharp