1
<?xml version="1.0" encoding="iso-8859-1"?>
2
<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
6
<firstname>Gerald</firstname><surname>Carter</surname>
8
<pubdate>October 2002</pubdate>
12
<title>Samba WINS Internals</title>
16
<title>WINS Failover</title>
20
The current Samba codebase possesses the capability to use groups of WINS
21
servers that share a common namespace for NetBIOS name registration and
22
resolution. The formal parameter syntax is
25
<para><programlisting>
26
WINS_SERVER_PARAM = SERVER [ SEPARATOR SERVER_LIST ]
27
WINS_SERVER_PARAM = "wins server"
31
SEPARATOR = comma | \s+
32
SERVER_LIST = SERVER [ SEPARATOR SERVER_LIST ]
33
</programlisting></para>
36
A simple example of a valid wins server setting is
39
<para><programlisting>
41
wins server = 192.168.1.2 192.168.1.3
42
</programlisting></para>
45
In the event that no TAG is defined in for a SERVER in the list, smbd assigns a default
46
TAG of "*". A TAG is used to group servers of a shared NetBIOS namespace together. Upon
47
startup, nmbd will attempt to register the netbios name value with one server in each
52
An example using tags to group WINS servers together is show here. Note that the use of
53
interface names in the tags is only by convention and is not a technical requirement.
57
<para><programlisting>
59
wins server = 192.168.1.2:eth0 192.168.1.3:eth0 192.168.2.2:eth1
60
</programlisting></para>
63
Using this configuration, nmbd would attempt to register the server's NetBIOS name
64
with one WINS server in each group. Because the "eth0" group has two servers, the
65
second server would only be used when a registration (or resolution) request to
66
the first server in that group timed out.
70
NetBIOS name resolution follows a similar pattern as name registration. When resolving
71
a NetBIOS name via WINS, smbd and other Samba programs will attempt to query a single WINS
72
server in a tagged group until either a positive response is obtained at least once or
73
until a server from every tagged group has responded negatively to the name query request.
74
If a timeout occurs when querying a specific WINS server, that server is marked as down to
75
prevent further timeouts and the next server in the WINS group is contacted. Once marked as
76
dead, Samba will not attempt to contact that server for name registration/resolution queries
77
for a period of 10 minutes.