So far we have discussed Broadcast and NetBIOS Name Servers (NBNS) as methods to resolve the name of other computers to IP addresses.
With Broadcast there is a lot of overhead involved, every hosts must receive broadcast and react to it by sending it up the stack to the application layer even if the information isn't for that computer.
Then second method was with NBNS or WINS server.
A NetBIOS server needs to perform three main functions:
When a WINS client initializes, NBT sends a name registration query (called NAMEREGISTRATIONREQUEST) message directly to the primary WINS server for that client. The name registration query includes the source (WINS client) IP address, the destination (WINS server) IP address, and the NetBIOS name to be registered.
If the WINS server is available and the NetBIOS name is not already registered in the database, the server replies to the client with a positive name registration response message (called NAMEREGISTRATIONRESPONSE). This response includes the IP address of the WINS client and WINS server to route the message to the WINS client, the NetBIOS name that has been registered, and the renewal interval, which is a TTL (Time To Live) duration for the NetBIOS name registration. After renewal interval expires, name is removed from database unless the WINS client renews the registration and is given a new renewal interval.
By default the renewal interval is 144 hours or four days. If the interval is shorten the network traffic increases and performance will likely decrease. If the interval is increased, then the database might be less likely to remain accurate. You must make sure that the renewal interval is the same for both the primary and secondary WINS servers.
The WINS client continuously attempts to renew its name registration every 1/8 of the initial refresh timeout until it gets a response from a WINS server (primary or secondary).
After a WINS client has received its first renewal from a WINS server, from then on, it attempts to renew its registration only after 50% of the renewal interval has expired, or until the WINS client is restarted.
When the WINS client initiates a normal shutdown, the WINS client sends one name release request directly to the WINS server for each of its registered NetBIOS names.
When a host running NBT attempts to execute a command containing a NetBIOS name, that NetBIOS name must be resolved to an IP address. NBT must resolve the NetBIOS name to an IP address.
The process of netBIOS name resolution involves checking the NetBIOS name mapping tables in various places until an entry is found that maps the NetBIOS name to an IP address.
The default for a host configured to use WINS for NetBIOS name resolution is the H-Node which means it uses NBNS (WINS server) and B-Node broadcsats to reslove NetBIOS names.
Once the NetBIOS name has been resolved, NBT adds the NetBIOS name and IP address mapping to the local NetBIOS Name Cache and does not query by using any of the other methods. It can then use IP to route datagrams to the destination NetBIOS host. If the NetBIOS name cannot be resolved to an IP address, NetBIOS cannot use TCP/IP to communicate with that host. (might see error message "The network path was not found") (see p. 265)
To view the NetBIOS Name Cache contents type the following command NBTSTAT -n
C:\>nbtstat -n
Node IpAddress: [56.88.21.239] Scope Id: []
NetBIOS Local Name Table
Name Type Status
---------------------------------------------
machine_name <00> UNIQUE Registered
domain_name <00> GROUP Registered
machine_name <03> UNIQUE Registered
machine_name <20> UNIQUE Registered
domain_name<1E> GROUP Registered
username <03> UNIQUE Registered
machine_name<01> UNIQUE Registered
Order of Resolution
Simple setup you need the following:
Installing WINS in a larger intranet:
This can either be done by typing in a Static address or leave it up to DHCP.
Static address:
DHCP clients configuration as WINS clients (two options)