How to Check Mail Aliases

To verify aliases and whether mail can be delivered to a given recipient:

Type /usr/lib/sendmail -v -bv recipient and press Return.

The command displays the aliases and identifies the final address as deliverable or not.

Here is an example of the output:

% /usr/lib/sendmail -v -bv sandy
sandy... aliased to   ssmith
ssmith... aliased to              sandy@phoenix
sandy@phoenix... deliverable: mailer esmtp, host phoenix, user sandy@phoenix.eng.acme.com
%

You should take extra care to avoid loops and inconsistent databases when both local and domain-wide aliases are used. Be especially careful when you move a user from one system to another to avoid creating alias loops.