0	user
0	user@localhost
0	user%localhost@localhost
0	barnett@crdgw1.ge.com
0	crdgw1.uucp!barnett
0	barnett@crdgw1.uucp
0       user@some.do.main
0       site!user%site2@site3.com
0	site1!site2!site3!user
0	site1!site2!site3!user@localhost
0	site1!site2!site3!user@machine.edu
0	site1!crd.ge.com!barnett
0	site1!crd.ge.com!barnett@crd.ge.com
0	user@bogus
22,4    user@crdgw1.UUCP  Sender_via_UUCP
