1Net::NBName(3) User Contributed Perl Documentation Net::NBName(3)
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6 Net::NBName - NetBIOS Name Service Requests
7
9 use Net::NBName;
10 my $nb = Net::NBName->new;
11 # a unicast node status request
13 my $ns = $nb->node_status("10.0.0.1");
14 if ($ns) {
15 print $ns->as_string;
16 }
17 # a unicast name query request
19 my $nq = $nb->name_query("10.0.1.80", "SPARK", 0x00);
20 if ($nq) {
21 print $nq->as_string;
22 }
23 # a broadcast name query request
25 my $nq = $nb->name_query(undef, "SPARK", 0x00);
26 if ($nq) {
27 print $nq->as_string;
28 }
29
31 Net::NBName is a class that allows you to perform simple NetBIOS Name
32 Service Requests in your Perl code. It performs these NetBIOS
33 operations over TCP/IP using Perl's built-in socket support.
34 I've currently implemented two NBNS requests: the node status request
36 and the name query request.
37 NetBIOS Node Status Request
39 This allows you to determine the registered NetBIOS names for a
40 specified remote host.
41 The decoded response is returned as a "Net::NBName::NodeStatus"
43 object.
44 querying 192.168.0.10 for node status...
46 SPARK <20> UNIQUE M-node Registered Active
47 SPARK <00> UNIQUE M-node Registered Active
48 PLAYGROUND <00> GROUP M-node Registered Active
49 PLAYGROUND <1C> GROUP M-node Registered Active
50 PLAYGROUND <1B> UNIQUE M-node Registered Active
51 PLAYGROUND <1E> GROUP M-node Registered Active
52 SPARK <03> UNIQUE M-node Registered Active
53 PLAYGROUND <1D> UNIQUE M-node Registered Active
54 ..__MSBROWSE__.<01> GROUP M-node Registered Active
55 MAC Address = 00-1C-2B-3A-49-58
56 NetBIOS Name Query Request
58 This allows you to resolve a name to an IP address using NetBIOS
59 Name Resolution. These requests can either be unicast (e.g. if you
60 are querying an NBNS server) or broadcast on the local subnet.
61 In either case, the decoded response is returned as an
63 "Net::NBName::NameQuery" object.
64 querying 192.168.0.10 for playground<00>...
66 255.255.255.255 GROUP B-node
67 ttl = 0 (default is 300000)
68 RA set, this was an NBNS server
69 broadcasting for playground<1C>...
71 192.168.0.10 GROUP B-node
72 ttl = 0 (default is 300000)
73 RA set, this was an NBNS server
74 broadcasting for spark<20>...
76 192.168.0.10 UNIQUE H-node
77 ttl = 0 (default is 300000)
78 RA set, this was an NBNS server
79
81 $nb = Net::NBName->new
82 Creates a new "Net::NBName" object. This can be used to perform
83 NetBIOS Name Service requests.
84
86 $ns = $nb->node_status( $host [, $timeout] )
87 This will query the host for its node status. The response will be
88 returned as a "Net::NBName::NodeStatus" object.
89 If no response is received from the host, the method will return
91 undef.
92 You can also optionally specify the timeout in seconds for the node
94 status request. The timeout defaults to .25 seconds.
95 $nq = $nb->name_query( $host, $name, $suffix [, $flags [, $timeout] ] )
97 This will query the host for the specified name. The response will
98 be returned as a "Net::NBName::NameQuery" object.
99 If $host is undef, then a broadcast name query will be performed;
101 otherwise, a unicast name query will be performed.
102 Broadcast name queries can sometimes receive multiple responses.
104 Only the first positive response will be decoded and returned as a
105 "Net::NBName::NameQuery" object.
106 If no response is received or a negative name query response is
108 received, the method will return undef.
109 You can override the flags in the NetBIOS name request, if you
111 *really* want to. See the notes on Hacking Name Query Flags.
112 You can also optionally specify the timeout in seconds for the name
114 query request. It defaults to .25 seconds for unicast name queries
115 and 1 second for broadcast name queries.
116
118 Querying NetBIOS Names
119 You can use this example to query for a NetBIOS name. If you specify a
120 host, it will perform a unicast query; if you don't specify a host, it
121 will perform a broadcast query. I've used the shorthand of specifying
122 the name as <name>#<suffix> where the suffix should be in hex.
123 "namequery.pl spark#0"
125 "namequery.pl spark#20 192.168.0.10"
127 use strict;
129 use Net::NBName;
130 my $nb = Net::NBName->new;
132 my $param = shift;
133 my $host = shift;
134 if ($param =~ /^([\w-]+)\#(\w{1,2})$/) {
135 my $name = $1;
136 my $suffix = hex $2;
137 my $nq;
139 if (defined($host) && $host =~ /\d+\.\d+\.\d+\.\d+/) {
140 printf "querying %s for %s<%02X>...\n", $host, $name, $suffix;
141 $nq = $nb->name_query($host, $name, $suffix);
142 } else {
143 printf "broadcasting for %s<%02X>...\n", $name, $suffix;
144 $nq = $nb->name_query(undef, $name, $suffix);
145 }
146 if ($nq) {
147 print $nq->as_string;
148 }
149 } else {
150 die "expected: <name>#<suffix> [<host>]\n";
151 }
152 Querying Remote Name Table
154 This example emulates the windows nbtstat -A command. By specifying the
155 ip address of the remote host, you can check its NetBIOS Name Table.
156 "nodestat.pl 192.168.0.10"
158 use Net::NBName;
160 my $nb = Net::NBName->new;
162 my $host = shift;
163 if (defined($host) && $host =~ /\d+\.\d+\.\d+\.\d+/) {
164 my $ns = $nb->node_status($host);
165 if ($ns) {
166 print $ns->as_string;
167 } else {
168 print "no response\n";
169 }
170 } else {
171 die "expected: <host>\n";
172 }
173 Scanning for NetBIOS hosts
175 This example can be used to scan for NetBIOS hosts on a subnet. It uses
176 Net::Netmask to parse the subnet parameter and enumerate the hosts in
177 that subnet.
178 "nodescan.pl 192.168.0.0/24"
180 use Net::NBName;
182 use Net::Netmask;
183 $mask = shift or die "expected: <subnet>\n";
185 $nb = Net::NBName->new;
187 $subnet = Net::Netmask->new2($mask);
188 for $ip ($subnet->enumerate) {
189 print "$ip ";
190 $ns = $nb->node_status($ip);
191 if ($ns) {
192 for my $rr ($ns->names) {
193 if ($rr->suffix == 0 && $rr->G eq "GROUP") {
194 $domain = $rr->name;
195 }
196 if ($rr->suffix == 3 && $rr->G eq "UNIQUE") {
197 $user = $rr->name;
198 }
199 if ($rr->suffix == 0 && $rr->G eq "UNIQUE") {
200 $machine = $rr->name unless $rr->name =~ /^IS~/;
201 }
202 }
203 $mac_address = $ns->mac_address;
204 print "$mac_address $domain\\$machine $user";
205 }
206 print "\n";
207 }
208
210 Microsoft's WINS Server Implementation
211 When performing name queries, you should note that when Microsoft
212 implemented their NBNS Name Server (Microsoft WINS Server) they mapped
213 group names to the single IP address 255.255.255.255 (the limited
214 broadcast address). In order to support real group names, Microsoft
215 modified WINS to provide support for special groups. These groups
216 appear differently in WINS. For example, the Domain Controllers (0x1C)
217 group appears as "Domain Name" instead of "Group".
218 The complete set of WINS mapping types is:
220 Unique
222 Group
223 Domain Name
224 Internet group
225 Multihomed
226 Unique and Group map to a single IP address. Domain Name, Internet
228 group, and Multihomed are special groups that can include up to 25 IP
229 addresses.
230 Hacking Name Query Flags
232 NetBIOS Name Service Requests have a number of flags associated with
233 them. These are set to sensible defaults by the code when sending node
234 status and name query requests.
235 However, it is possible to override these settings by calling the
237 name_query method of a "Net::NBName" object with a fourth parameter:
238 $nb->name_query( $host, $name, $suffix, $flags );
240 For a unicast name query, the flags default to 0x0100 which sets the RD
242 (recursion desired) flag. For a broadcast name query, the flags default
243 to 0x0010 which sets the B (broadcast) flag.
244 Experimentation gave the following results:
246 • If B is set, the remote name table will be used. There will be no
248 response if the queried name is not present.
249 • If B is not set and the host is an NBNS server, the NBNS server
251 will be used before the remote name table and you will get a
252 negative response if the name is not present; if the host is not an
253 NBNS server, you will get no response if the name is not present.
254
256 Copyright (c) 2002, 2003, 2004 James Macfarlane. All rights reserved.
257 This program is free software; you can redistribute it and/or modify it
258 under the same terms as Perl itself.
259perl v5.32.1 2021-01-27 Net::NBName(3)