1NSLOOKUP(1) General Commands Manual NSLOOKUP(1)
2
6 nslookup - query name servers interactively
7
9 nslookup [ host-to-find | - [ server address | server name ]]
10
12 Nslookup is a program to query DARPA Internet domain name servers.
13 Nslookup has two modes: interactive and non-interactive. Interactive
14 mode allows the user to query the name server for information about
15 various hosts and domains or print a list of hosts in the domain.
16 Non-interactive mode is used to print just the name and Internet
17 address of a host or domain.
18
21 Interactive mode is entered in the following cases:
22 a) when no arguments are given (the default name server will be used),
24 and
25 b) when the first argument is a hyphen (-) and the second argument is
27 the host name of a name server.
28 Non-interactive mode is used when the name of the host to be looked up
30 is given as the first argument. The optional second argument specifies
31 a name server.
32
35 Commands may be interrupted at any time by typing a control-C. To
36 exit, type a control-D (EOF). The command line length must be less
37 than 80 characters. N.B. an unrecognized command will be interpreted
38 as a host name.
39 host [server]
42 Look up information for host using the current default server or
43 using server if it is specified.
44 server domain
47 lserver domain
48 Change the default server to domain. Lserver uses the initial
49 server to look up information about domain while server uses the
50 current default server. If an authoritative answer can't be
51 found, the names of servers that might have the answer are
52 returned.
53 root Changes the default server to the server for the root of the
56 domain name space. Currently, the host sri-nic.arpa is used.
57 (This command is a synonym for the lserver sri-nic.arpa.) The
58 name of the root server can be changed with the set root com‐
59 mand.
60 finger [name] [> filename]
63 finger [name] [>> filename]
64 Connects with the finger server on the current host. The cur‐
65 rent host is defined when a previous lookup for a host was suc‐
66 cessful and returned address information (see the set query‐
67 type=A command). Name is optional. > and >> can be used to re‐
68 direct output in the usual manner.
69 ls domain [> filename]
72 ls domain [>> filename]
73 ls -a domain [> filename]
74 ls -a domain [>> filename]
75 ls -h domain [> filename]
76 ls -h domain [>> filename]
77 ls -d domain [> filename]
79 List the information available for domain. The default output
80 contains host names and their Internet addresses. The -a option
81 lists aliases of hosts in the domain. The -h option lists CPU
82 and operating system information for the domain. The -d option
83 lists all contents of a zone transfer. When output is directed
84 to a file, hash marks are printed for every 50 records received
85 from the server.
86 view filename
89 Sorts and lists the output of previous ls command(s) with
90 more(1).
91 help
94 ? Prints a brief summary of commands.
96 set keyword[=value]
99 This command is used to change state information that affects
100 the lookups. Valid keywords are:
101 all Prints the current values of the various options to set.
103 Information about the current default server and host is
104 also printed.
105 [no]debug
107 Turn debugging mode on. A lot more information is printed
108 about the packet sent to the server and the resulting
109 answer.
110 (Default = nodebug, abbreviation = [no]deb)
111 [no]d2 Turn exhaustive debugging mode on. Essentially all
113 fields of every packet are printed.
114 (Default = nod2)
115 [no]defname
117 Append the default domain name to every lookup.
118 (Default = defname, abbreviation = [no]def)
119 [no]search
121 With defname, search for each name in parent domains of
122 the current domain.
123 (Default = search)
124 domain=name
126 Change the default domain name to name. The default
127 domain name is appended to all lookup requests if the
128 defname option has been set. The search list is set to
129 parents of the domain with at least two components in
130 their names.
131 (Default = value in hostname or /etc/resolv.conf, abbre‐
132 viation = do)
133 querytype=value
135 type=value
137 Change the type of information returned from a query to
138 one of:
139 A the host's Internet address (the default).
141 CNAME the canonical name for an alias.
143 HINFO the host CPU and operating system type.
145 MD the mail destination.
147 MX the mail exchanger.
149 MG the mail group member.
151 MINFO the mailbox or mail list information.
153 MR the mail rename domain name.
155 NS nameserver for the named zone.
157 Other types specified in the RFC883 document are valid but
158 aren't very useful.
159 (Abbreviation = q)
160 [no]recurse
162 Tell the name server to query other servers if it does
163 not have the information.
164 (Default = recurse, abbreviation = [no]rec)
165 retry=number
167 Set the number of retries to number. When a reply to a
168 request is not received within a certain amount of time
169 (changed with set timeout), the request is resent. The
170 retry value controls how many times a request is resent
171 before giving up.
172 (Default = 2, abbreviation = ret)
173 root=host
175 Change the name of the root server to host. This affects
176 the root command.
177 (Default = sri-nic.arpa, abbreviation = ro)
178 timeout=number
180 Change the time-out interval for waiting for a reply to
181 number seconds.
182 (Default = 10 seconds, abbreviation = t)
183 [no]vc Always use a virtual circuit when sending requests to the
185 server.
186 (Default = novc, abbreviation = [no]v)
187
189 If the lookup request was not successful, an error message is printed.
190 Possible errors are:
191 Time-out
193 The server did not respond to a request after a certain amount
194 of time (changed with set timeout=value) and a certain number of
195 retries (changed with set retry=value).
196 No information
198 Depending on the query type set with the set querytype command,
199 no information about the host was available, though the host
200 name is valid.
201 Non-existent domain
203 The host or domain name does not exist.
204 Connection refused
206 Network is unreachable
207 The connection to the name or finger server could not be made at
208 the current time. This error commonly occurs with finger
209 requests.
210 Server failure
212 The name server found an internal inconsistency in its database
213 and could not return a valid answer.
214 Refused
216 The name server refused to service the request.
217 The following error should not occur and it indicates a bug in the pro‐
220 gram.
221 Format error
223 The name server found that the request packet was not in the
224 proper format.
225
228 /etc/resolv.conf initial domain name and name server addresses.
229
231 resolver(3), resolver(5), named(8), RFC882, RFC883
232
234 Andrew Cherenson
2354.3 Berkeley Distribution November 21, 1987 NSLOOKUP(1)