While at work one day this week, users started complaining about slow access times to a particular application. After confirming that all applicable servers (an application server and a SQL server) were online, and that there were no SQL problems (such as deadlocks), we took a look at the event log, and found an obscure entry:
Type: Error
Source: Userenv
Event ID: 1000
Description: Windows cannot determine the user or computer name. Return value (1722).
Like many good event log messages this told me little about the actual problem. Rather than scratch my head until an answer mysteriously appeared, I went to perhaps the best resource for understanding event log entries: EventID.net (www.eventid.net).
EventID.net provides a searchable index to events, and has extensive information provided by other users that can be invaluable in troubleshooting problems. Using the site is simple: enter the event ID number and the source and click a search button. The site returns a list of possible matches, including descriptions. Find the one that matches your problem the best and click a link to obtain the details.
In my case, a search for “event ID 1000, source Userenv” brought me to a results page with a few dozen hits. One of those hits matched my event, so I went to the details page. There’s a lot of information here provided from other users, and one common thread in their posts: check your DNS servers and settings.
Sure enough, there were two problems. This server never had its primary DNS server updated some months ago when we changed DNS servers. Further, we also found out that the secondary server, which was previously processing all DNS requests for this server, had stopped running. We changed the primary DNS server and within a minute were operating normally.
The moral of this story: Look at the event log periodically and whenever there is a problem that doesn’t have a clear solution, and when you do, be sure to use resources such as EventID.net to get a complete understanding of the problem and to use other people’s experiences to solve your problem more quickly.