Any idea why I would be seeing >75 Failed Logins Per Hour on one of my 6.5 OES NW SP4 server

Time: Monday, 10-03-2005 10:02 am
Address: IP 10.30.10.228
User: .OU=STUDENT.OU=STUSERVERS.O=TMC.T=TMC_TREE.

Time: Monday, 10-03-2005 10:02 am
Address: IP 10.30.10.228
User: .OU=STUDENT.OU=STUSERVERS.O=TMC.T=TMC_TREE.

Time: Monday, 10-03-2005 10:02 am
Address: IP 10.30.10.228
User: .OU=STUDENT.OU=STUSERVERS.O=TMC.T=TMC_TREE.

Time: Monday, 10-03-2005 9:55 am
Address: IP 10.30.10.178
User: .OU=STUDENT.OU=STUSERVERS.O=TMC.T=TMC_TREE.

Time: Monday, 10-03-2005 9:55 am
Address: IP 10.30.10.178
User: .OU=STUDENT.OU=STUSERVERS.O=TMC.T=TMC_TREE.

Time: Monday, 10-03-2005 9:55 am
Address: IP 10.10.02.53
User: .CN=MTA.CN=TMC_DOM.O=TMC.T=TMC_TREE.

Time: Monday, 10-03-2005 9:55 am
Address: IP 10.30.10.178
User: .OU=STUDENT.OU=STUSERVERS.O=TMC.T=TMC_TREE.

Time: Monday, 10-03-2005 9:55 am
Address: IP 10.10.02.53
User: .CN=MTA.CN=TMC_DOM.O=TMC.T=TMC_TREE.

Time: Monday, 10-03-2005 9:52 am
Address: IP 10.30.10.36
User: .OU=STUDENT.OU=STUSERVERS.O=TMC.T=TMC_TREE.