Browser Requests

The purpose of the browser service is to make a list of network resources available to browser clients. To use this resource list, the browser client must know which computer to contact to request a copy of the list.

Figure I.5 shows the flow of browser request.

Figure I.5 Flow of the Browser Request

The request issued to obtain the list of available network resources is a NetServerEnum API call. This request is sent when net view is run at the command prompt and when Browse button is selected from the Map Network Drive dialog box. The client issues the NetServerEnum API call to a backup browser.

Before a client can send a NetServerEnum API call for the first time, it must first discover which computers are the backup browsers for its workgroup or domain. The client does this by issuing a datagram called GetBackupList to the master browser.

The master browser receives and processes the GetBackupList datagram. The master browser returns a list of backup browsers active within the workgroup or domain being queried. The client selects the names of three backup browsers from the list and stores these names for future use. The NetServerEnum API call is sent to a backup browser randomly chosen from the three saved names.

If the master browser for the workgroup or domain being queried cannot be found after three attempts, the client forces the election of a new master browser in the domain. The client also returns the message ERROR_BAD_NETPATH to the browsing application, indicating that the master browser cannot be found.