I'm getting a number of failed logins on different (unrelated) servers with this recurring content:

Time: Wednesday, 4-22-2009 8:23 am
Address:
User: Unknown (ID=-1387086512)

Time: Wednesday, 4-22-2009 8:12 am
Address:
User: Unknown (ID=-1385051696)

Time: Wednesday, 4-22-2009 7:13 am
Address:
User: Unknown (ID=-1383904080)
Note that the Address is blank, so that's not helpfule, and the User is "Unknown" withe a negative ID number, that is different each time. I'd sure like to be able to track this down and clean up these failed logins, but with only the unusual ID= number, it doesn't give me much to go on.