Route–Independent Mail Addresses

Mail addresses can be route independent. Route-independent addressing requires the sender of an email message to specify the name of the recipient and the final destination. A high-speed network, such as the Internet, uses route-independent addresses. Route-independent addresses can have this format.

user@host.domain

Route-independent addresses for UUCP connections can have this address format.

host.domain!user

The increased popularity of the domain-hierarchical naming scheme for computers is making route-independent addresses more common. Actually, the most common route-independent address omits the host name and relies on the domain name service to properly identify the final destination of the email message.

user@domain

Route-independent addresses are first read by searching for the @ sign. The domain hierarchy is then read from the right (the highest level) to the left (the most specific part of the address to the right of the @ sign).