9.6 Helpful Hints

The following hints should be carefully considered as they are stumbling points for many new network administrators.

9.6.1 Windows Networking Protocols

W ARNING

Do not use more than one protocol on MS Windows machines.

A common cause of browsing problems results from installing more than one protocol on an MS Windows machine.

Every NetBIOS machine takes part in a process of electing the LMB (and DMB) every 15 minutes. A set of election criteria is used to determine the order of precedence for winning this election process. A machine running Samba or Windows NT will be biased so the most suitable machine will predictably win and thus retain its role.

The election process is " fought out " so to speak over every NetBIOS network interface. In the case of a Windows 9x/Me machine that has both TCP/IP and IPX installed and has NetBIOS enabled over both protocols, the election will be decided over both protocols. As often happens, if the Windows 9x/Me machine is the only one with both protocols then the LMB may be won on the NetBIOS interface over the IPX protocol. Samba will then lose the LMB role as Windows 9x/Me will insist it knows who the LMB is. Samba will then cease to function as an LMB and thus browse list operation on all TCP/IP-only machines will fail.

Windows 95, 98, 98se, and Me are referred to generically as Windows 9x/Me. The Windows NT4, 200x, and XP use common protocols. These are roughly referred to as the Windows NT family, but it should be recognized that 2000 and XP/2003 introduce new protocol extensions that cause them to behave differently from MS Windows NT4. Generally, where a server does not support the newer or extended protocol, these will fall back to the NT4 protocols.

The safest rule of all to follow is: use only one protocol!

9.6.2 Name Resolution Order

Resolution of NetBIOS names to IP addresses can take place using a number of methods . The only ones that can provide NetBIOS name_type information are:

• WINS ” the best tool.

• LMHOSTS ” static and hard to maintain.

• Broadcast ” uses UDP and cannot resolve names across remote segments.

Alternative means of name resolution include:

• Static /etc/ hosts ” hard to maintain, and lacks name_type info .

• DNS ” is a good choice but lacks essential name_type info.

Many sites want to restrict DNS lookups and avoid broadcast name resolution traffic. The name resolve order parameter is of great help here. The syntax of the name resolve order parameter is:

  name resolve order = wins lmhosts bcast host  

or

  name resolve order = wins lmhosts (eliminates bcast and host)  

The default is:

  name resolve order = host lmhost wins bcast  

where " host " refers to the native methods used by the UNIX system to implement the gethostbyname() function call. This is normally controlled by /etc/host.conf , /etc/nsswitch.conf and /etc/resolv.conf .