Troubleshooting a WINS Server in Windows 2003
In the early days of NT 4.0, WINS was plagued with problems, in fact it seemed to me that half the fixes in NT services packs were for WINS Jet database errors. Thankfully all those problems have been ironed out. In fact it seems a shame that now that WINS is working perfectly, it has become obsolete.
Topics for Troubleshooting WINS Servers
- Basic ping problems
- Cannot see any Resource Records
- NBTStat and WINS Records
- NetBIOS Name Resolution Sequence
- Backup WINS Database
- Compacting the WINS Database
- Burst handling
- WINS Summary
A common problem is that you can ping a server by IP address, but not by NetBIOS name. The first place to check is the WINS database. If the record is there, and you can ping correctly from the server itself, then blame the client’s WINS settings. Either DHCP has an error in Option 044 or 046, or there is a fault at the clients TCP/IP properties. In the latter case check the Network connection properties.
Add the WINS server’s own IP address to its database.
This can be embarrassing. You know that clients have registered in WINS server but When you go to the WINS Server icon, you cannot see any records in the Active Registrations folder. The solution is simply right-click Active Registrations, and select Display Records. The crucial step is just click on the button: Find now.
NBTStat is a handy command line utility to connect interrogate a WINS server. You can discover which resource records the WINS server holds for which host.
To save the long walk to the WINS server, you could either user Remote Desktop, or go to the command line and try NBTStat. (Careful with the spelling as there is also a netstat.) Collect information about WINS records by going to the cmd prompt and typing, NBTStat – A (Big A), for example:
nbtstat – A 192.168.0.23.
Beware NBTStat is a rare utility in that its switches are case sensitive e.g. NBTStat -a and -A give different results. Here are two examples:
Lower case ‘-a’ will only be effective with the ServerName for example:
nbtstat -a ServerName. Do not use the IP address with -a.
Upper case ‘-A’ requires an IP address for example
nbtstat -A 192.168.0.23. However -A ServerName fails.
Another point is that (-a and -A are designed for remote machines, to see your very own WINS records type nbtstat -n (no ip address or NetBIOS name required)
When you are troubleshooting it saves time if you know the default sequence that a client uses to resolve a NetBIOS name request.
- Looks in it’s own NetBIOS cache. You can check this cache with nbtstat -n (also -c for any remote machines cached).
- Queries WINS.
- Broadcast. Tell the truth the reason that I have taken my eye of the NetBIOS ball is that in testing all my machines have been on the same network. So as broadcast is a valid method for NetBIOS name resolution, I had not needed the WINS server. But in the real world, servers will be on other networks, so we will need WINS. (Broadcasts, by definition, are limited to the subnet where they originate.)
- Looks in LMHosts. To this LMHosts and Hosts files are a life saver when troubleshooting.
Incidentally, there used to be the trick question that LMHosts reduced broadcasts, well you can see from this sequence that LMHosts has no effect on broadcasting (more’s the pity).
- Here is the slightly strange part, if the client has not yet received an answer to its NetBIOS query, it now checks the hosts file and then DNS.
SolarWinds’ Network Performance Monitor will help you discover what’s happening on your network. This utility will also guide you through troubleshooting; the dashboard will indicate whether the root cause is a broken link, faulty equipment or resource overload.
Perhaps the NPM’s best feature is the way it suggests solutions to network problems. Its second best feature is the ability to monitor the health of individual VMware virtual machines. If you are interested in troubleshooting, and creating network maps, then I recommend that you give this Network Performance Monitor a try.
The notorious WINS backup problem occurs when you try and backup WINS, not locally, but across the network. All that you can do is change the Database path back to a local folder.
To alter the path, launch the WINS manager and navigate to the Server icon, right-click and select the advanced tab of the properties. Traditionally, the path is %windir%\system32\wins.
In fact, one reason for backing up the WINS database is that you wish to protect wins.mdb against a compact error.
If you have a large number of WINS clients then every 6 months or so, you should reclaim diskspace space by compacting the WINS server database.
Instructions to Compact wins.mdb
- Stop with WINS service – net stop wins
- Navigate to the %windir%\system32\wins folder
- Type – Compact. (Just run the compact command to see what files are there. You should see wins.mdb.)
- Type – Compact /c wins.mdb (Note some impressive compression ratios.)
- Start the WINS service – net start wins
NetSH is on my list of: – can do better with this program. My point if you like NetSH then WINS would be one reason to practice with this command-line utility.
It puzzled me how switching to ‘burst handling’ would speed up the WINS service. Then all became clear when I realized that what happens is that WINS receives requests for registration, but defers adding or updating the records. Like any good TCP transaction, when the client sends in request to be registered the server should respond, with burst mode the servers replies instantly, but actually puts the request in a queue to be registered with the server is less busy. Without burst handling, the client’s request would timeout and so it would send another request so increasing the load on the server and exacerbating the problem.
A likely scenario is that all the users turn on their machines at the same time on a Monday morning, so swamp the WINS server registration request. My friend ‘Mad Mick’ said one of his clients suffered from frequent power cuts, and the burst mode helped to reduce the load when all the computers restarted at the same time.
Indication that burst handing is working is error code
4338 – WINS_EVT_SPOOFING_STARTED in the application code. If fact the message is asking you to adjust the setting on the Advanced tab on the WINS server.
To configure Burst mode launch the WINS snap-in and navigate to the Server icon, Advanced tab. The higher the burst handling setting, the bigger the queue or buffer on the server. So if you set burst handling to high the server supports a queue of up to 500 pending registration requests.
Kiwi CatTools is a free program for backing up configuration settings on hardware devices. Here is Guy’s challenge. If you download CatTools, then it will not only take care of backups, but also it will show you something new about the hardware on you network. I could give you a money back guarantee – but CatTools is already free! Thus, I just make a techie to techie challenge, you will learn more about your network if you:
There is a troubleshooting tool for every WINS problem. From NBTStat at the command line, to burst handing at the WINS Server.
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