I run an outbound gateway (4 nodes) behind a F5 which shall (sic) be
relocated into a diffrent network and the new LB can't preserve the senders
IP but can do proxy protocol...
Currently I do use smtp_accept_reserve / smtp_reserve_hosts to ensure
the top sending ips get a free slot and helo_accept_junk_hosts for a few
IPs ...
I guess those must be reworked as well as black-listing per IP in
acl_check_connect and rate-limiting in acl_check_rcpt?
