Server Health Checks – 3
Check NLBS Configurations
1. Open up the network properties –> Network Load Balancing, right click & select Properties
2. On the Cluster Parameters tab, verify that the IP address is configured for the shared NLBS IP and that the subnet mask, domain, and operation mode are configured correctly.
3. On the Host Parameters tab, make sure each node of the cluster has a unique host identifier. Also verify the IP and subnet mask are configured for the local values.
4. Also make sure that your switch has a static ARP entry if using multi-cast NLBS. The entry should be that of the virtual MAC of the cluster. To get the virtual MAC of the cluster, you can run the following command : WLBS IP2MAC <virtual IP address>
Name Resolution
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To healthcheck name resolution, open a command prompt and enter the following
· nslookup <servername>
Verify that the servername is correctly entered in DNS
If a record does not show up in the DNS query, or maps to a different name, perform a reverse lookup by IP address to see what name is associated with the IP address * nslookup <IP address>
If no name shows up associated with the IP address, log into the domain controller and check the DNS records for this particular name/ip address
1. From a Domain Controller go to start–>run–>dnsmgmt.msc
2. Expand the Forward Lookup Zones
3. Expand the zone for you primary zone that holds the records for the system/s you are troubleshooting
Validate that the record exists. If it does not exist manually enter the record name and IP address by right clicking on this same zone,
1. Select new host (a)
2. Enter the name and IP address
3. Check the box next to Create associated pointer (PTR) record
4. Click add Host
Additionally log back into the node that you manually entered the record for and ensure that DNS is registering in DNS
1. Right click on the My Network Places icon on the desktop and select Properties
2. Double click on the primary adapter
3. Select properties
4. Highlight internet protocol (TCP/IP) and select properties
5. Validate the IP addresses of the DNS servers are correct
6. Select Advanced
7. Select DNS tab
8. Make sure the box is checked next to Register this connection’s address in DNS
As I wrap this up I realize there is so much more that can be done. Each application type of server needs its own set off health checks. For example web servers, terminal servers and database servers. Remember this is just the baseline for each server and that other components can and should be layered on top of it. Again I would love to hear from others so please feel free to add you comments below.