Nortel Networks NN46110-602 - Manual (Page 87)

Chapter 4 Troubleshooting 87
Nortel VPN Router Troubleshooting
To specify a computer as the preferred master browser, set the parameter for
IsDomainMasterBrowser to True or Yes in the following registry path:
\HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Browser\
Parameters
Unless the computer is configured as the preferred master browser, the parameter
entry is always False or No. There is no user interface for making these changes;
you must modify the registry.
Why are subnet masks important?
If a client does not have a WINS server or is unable to contact it, it must broadcast
a query to try to locate a host. Unfortunately, Windows 95, Windows 98, and
Windows NT clients do not always use the correct broadcast address when
tunneling.
The following example helps explain this problem. Suppose that you are using a
private net 10 address space. Assume further that you have a client with IP address
10.1.2.3 and subnet mask 255.255.0.0. This means that the net 10 space is used
like a class B address space, which is perfectly legal. The correct broadcast for
this client is 10.1.255.255. However, Microsoft clients can broadcast to
10.255.255.255, using the natural class A for net 10, in spite of their
configuration.
If all hosts that the client is trying to reach lie on the same physical segment, this
probably will work. This is because every host on the physical network receives
the all subnets broadcast and probably responds, if appropriate.
All hosts on the segment receive the broadcast to 10.255.255.255, even if they are
on different subnets (10.1.x.x. and 10.2.x.x). However, in a routed environment
the situation changes. In this case, a broadcast from 10.1.2.3 to 10.255.255.255 is
not forwarded to the other 10.2 subnet.
In the extranet environment, make the remote client appear as much as possible to
be on the local LAN. If the extranet host is assigned address 10.1.2.3, it should
behave as if it is on the 10.1 LAN.