Etherpad emails show wrong port (9000) when sending from version 1 running apache and mod_proxy
Etherpad emails may show as port 9000 if you are using mod_proxy(apache) in front of etherpad.
If this is a problem simply edit:
/usr/share/etherpad/etherpad/etc/etherpad.local.properties replacing hidePorts = false with hidePorts = true