Smart host

A smart host or smarthost is an email server via which third parties can send emails and have them forwarded on to the email recipients' email servers. Smarthosts were originally open mail relays, but most providers now requiring authentication from the sender, to verify that the sender is authorised - for example, an ISP might run a smarthost for their paying customers only.

Smart host

A smart host or smarthost is an email server via which third parties can send emails and have them forwarded on to the email recipients' email servers. Smarthosts were originally open mail relays, but most providers now requiring authentication from the sender, to verify that the sender is authorised - for example, an ISP might run a smarthost for their paying customers only.