The following sections provide some tips and tools that you can use for troubleshooting mail.
To verify aliases and determine 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. The following example shows the output from this command.
% /usr/lib/sendmail -v -bv shamira@raks shamira... aliased to mwong mwong... aliased to shamira@raks shamira@raks... deliverable %
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 ...