|Contents||Bulletin||Scripting in shell and Perl||Network troubleshooting||History||Humor|
|News||See Also||Recommended Books||dig||Perl-based DNS Tools||Online DNS Tools||DNS Zone Generators|
Two classic tools are nslookup and dig.
Although dig is more convenient, you can get a version of a nameserver using nslookup:
> set q=txt
> set class=chaos
VERSION.BIND text = "8.2.2-P7"
Queries Internet domain name servers.
nslookup [ -Option ... ] [ Host ] [ -NameServer ]
The nslookup command queries Internet domain name servers in two modes. Interactive mode allows you to query name servers for information about various hosts and domains, or to print a list of the hosts in a domain. In noninteractive mode, the names and requested information are printed for a specified host or domain.
The nslookup command enters interactive mode when no arguments are given, or when the first argument is a - (minus sign) and the second argument is the host name or Internet address of a name server. When no arguments are given, the command queries the default name server. The - (minus sign) invokes an optional subcommand (-Option... variable). With the exception of the set command, these subcommands are specified on the command line and must precede the nslookup command arguments. The set subcommand options can alternatively be specified in the .nslookuprc file in the user's home directory.
The nslookup command executes in noninteractive mode when the first argument is the name or Internet address of the host being searched for. In this case, the host name or Internet address of the name server is optional.
The noninteractive command looks up information for the specified Host using the default name server or the name server specified by the NameServer parameter. If the Host parameter specifies an Internet address and the query type is A or PTR, the name of the host is returned. If the Host parameter specifies a name and the name does not have a trailing period, the default domain name is appended to the name. To look up a host not in the current domain, append a single period to the name.
Note: If they are specified in the .nslookuprc file of the user's home directory, the set subcommand's domain, srchlist, defname, and search options can affect the behavior of the noninteractive command.
The following commands can be interrupted at any time by entering a Ctrl-C key sequence. To exit, enter a Ctrl-D key sequence or type exit. To treat a built-in command as a host name, precede it with an escape character, which is a \. Unrecognized commands are interpreted as host names.
The following subcommands are recognized by the nslookup command:
finger [Name] [>> FileName]
|Connects with the finger daemon server on the current host. The current host is defined when a previous lookup for a host was successful and returned address information, such as that returned with the set querytype=A command. The Name parameter, which specifies a user name, is optional. The > and >> characters can be used to redirect output to a new or existing file.|
|Changes the default server to the value specified by the Domain parameter. The lserver subcommand uses the initial server to look up information about the domain. The server subcommand uses the current default server. If an authoritative answer cannot be found, the names of any additional servers that might have the answer are returned.|
|root||Changes the default server to the server for the root of the domain name space. Currently, the host ns.nic.ddn.mil is used. The name of the root server can be changed with the set root subcommand. (The root subcommand is synonymous with the lserver ns.nic.ddn.mil subcommand.)|
ls [Option] Domain [>> FileName]
|Lists the information available for the
Domain specified, optionally creating
or appending the output to the file specified by the
FileName parameter. The default
output contains host names and their Internet addresses. Possible
values for the Option parameter
Note: When output is redirected to a file, hash marks are printed for every 50 records received from the server.
|view FileName||Sorts the output of previous ls commands and lists them using the more command.|
|?||Prints a brief summary of commands.|
|exit||Exits the program.|
|set Keyword[=Value]||Changes state information that affects lookups. This subcommand
can be specified on the command line or optionally included
in the .nslookuprc file in the user's
home directory. Valid keywords are:
|type=Value||Changes the information query to one of the following values.
The default is A.
nslookup -query=hinfo -timeout=10
nslookup -set srchlist=lcs.MIT.EDU/ai.MIT.EDU/MIT.EDU
This command overrides the default domain name and search list of the set domain command. Use the set all command to display the list.
nslookup -querytype=ANY austin.ibm.com
The nslookup command returns all available information about the name austin.ibm.com, including Statement of Authority (SOA), name server, mail exchanger, and host Internet address information, as follows:
Server: benames.austin.ibm.com Address: 18.104.22.168 austin.ibm.com origin = ausname1.austin.ibm.com mail addr = brian.chriss.austin.ibm.com serial=1993081210,refresh=3600,retry=300,expire=604800, min=86400 austin.ibm.com nameserver = ausname1.austin.ibm.com austin.ibm.com nameserver = bb3names.austin.ibm.com austin.ibm.com nameserver = benames.austin.ibm.com austin.ibm.com nameserver = b45names.austin.ibm.com austin.ibm.com nameserver = bbcnames.austin.ibm.com austin.ibm.com nameserver = netmail.austin.ibm.com austin.ibm.com preference = 10, mail exchanger = netmail.austin.ibm.com austin.ibm.com inet address = 22.214.171.124 ausname1.austin.ibm.com inet address = 126.96.36.199 bb3names.austin.ibm.com inet address = 188.8.131.52 benames.austin.ibm.com inet address = 184.108.40.206 b45names.austin.ibm.com inet address = 220.127.116.11 bbcnames.austin.ibm.com inet address = 18.104.22.168 netmail.austin.ibm.com inet address = 22.214.171.124
The nslookup command responds similarly to the host command. The command returns the domain name and Internet address of host opus, as follows:
Name: opus.austin.ibm.com Address: 126.96.36.199
If host opus had been a name server (a host running the named daemon with an empty /etc/resolv.conf file), the following information would have been displayed:
Server: loopback Address: 0.0.0.0
When a lookup request is not successful, the nslookup command returns one of the following error messages:
|Timed Out||Indicates the server did not respond to the request after the specified number of retries.|
|No Response from Server||Indicates that a name server is not running on the server machine.|
|No Records||Indicates the server does not have the resource records of the specified query type for the host, although the host name is valid.|
|Non-Existent Domain||Indicates the host or domain name does not exist.|
|Connection Refused||Indicates the connection to the name or finger server could not be made at the time of the inquiry. This error is typically associated with ls and finger requests.|
|Network Is Unreachable||Indicates the connection to the name or finger server could not be made at the time of the inquiry. This error is typically associated with ls and finger requests.|
|Server Failure||Indicates the name server encountered an internal inconsistency and could not return a valid answer.|
|Refused||Indicates the name server refused to service the request.|
|Format Error||Indicates the name server refused the request packet because it was not in the proper format.|
|/usr/bin/nslookup||Contains the nslookup command.|
|/etc/resolv.conf||Contains the initial domain name and nameserver addresses.|
|$HOME/.nslookuprc||Contains the user's initial options.|
|HOSTALIASES||Contains the host aliases.|
|LOCALDOMAIN||Contains the override default domain.|
namerslv command, traceroute command.
res_query subroutine, res_search subroutine.
resolv.conf file format for TCP/IP.
TCP/IP Name Resolution in AIX 5L Version 5.3 System Management Guide: Communications and Networks.
FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available in our efforts to advance understanding of environmental, political, human rights, economic, democracy, scientific, and social justice issues, etc. We believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit exclusivly for research and educational purposes. If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner.
ABUSE: IPs or network segments from which we detect a stream of probes might be blocked for no less then 90 days. Multiple types of probes increase this period.
Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers : Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism : The Iron Law of Oligarchy : Libertarian Philosophy
War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda : SE quotes : Language Design and Programming Quotes : Random IT-related quotes : Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce : Bernard Shaw : Mark Twain Quotes
Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 : Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law
Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds : Larry Wall : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOS : Programming Languages History : PL/1 : Simula 67 : C : History of GCC development : Scripting Languages : Perl history : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history
The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month : How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Haterís Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite
Most popular humor pages:
Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor
The Last but not Least
Copyright © 1996-2016 by Dr. Nikolai Bezroukov. www.softpanorama.org was created as a service to the UN Sustainable Development Networking Programme (SDNP) in the author free time. This document is an industrial compilation designed and created exclusively for educational use and is distributed under the Softpanorama Content License.
Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.
FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available to advance understanding of computer science, IT technology, economic, scientific, and social issues. We believe this constitutes a 'fair use' of any such copyrighted material as provided by section 107 of the US Copyright Law according to which such material can be distributed without profit exclusively for research and educational purposes.
This is a Spartan WHYFF (We Help You For Free) site written by people for whom English is not a native language. Grammar and spelling errors should be expected. The site contain some broken links as it develops like a living tree...
|You can use PayPal to make a contribution, supporting development of this site and speed up access. In case softpanorama.org is down you can use the at softpanorama.info|
The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the author present and former employers, SDNP or any other organization the author may be associated with. We do not warrant the correctness of the information provided or its fitness for any purpose.
Created May 16, 1996; Last modified: October 20, 2015