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Classic DNS Tools

News DNS Tools Recommended Links dig - DNS lookup utility nslookup hostname
DNS Zone generators Online DNS Tools DNS Audit Scripts DNS Tips Humor Etc

There are three tools that can be considered classic DNS tools: nslookup, dig and hostname.

nslookup

nslookup is a network administration command-line tool available for many computer operating systems for querying the Domain Name System (DNS) to obtain domain name or IP address mapping or for any other specific DNS record.

See nslookup

Although dig is more convenient, you can get a version of a nameserver using nslookup:

> set q=txt

> set class=chaos

> version.bind

Server: ns.nowhere.some-corp.com

Address: 131.1.11.9

VERSION.BIND text = "8.2.2-P7"

Dig

Domain Information Groper (dig) is a network administration command-line tool for querying Domain Name System (DNS) name servers for any desired DNS records. See dig - DNS lookup utility

Dig is useful for network troubleshooting and for educational purposes. Dig can operate in interactive command line mode or in batch mode by reading requests from an operating system file. When a specific name server is not specified in the command invocation, it will use the operating systems default resolver, usually configured via the resolv.conf file. Without any arguments it queries the DNS root zone.

Dig supports Internationalized Domain Name (IDN) queries.

Dig is part of the BIND domain name server software suite. Dig replaces older tools such as nslookup and the host program.

 

Network Ice Corporation. "dig." 2000.
URL: http://www.netice.com/advice/Reference/Tools/dig/default.htm (22 July, 2000).

The IP troubleshooters page contains a lot of interesting pointers on documents and tools, and to public gateways to use whois, nslookup, ping, traceroute.

digfe is a GUI interface for dig, the DNS client program. http://www.concoctedlogic.com/digfe/

Hostname

hostname - show or set the system's host name

hostname [-v] [-a] [--alias] [-d] [--domain] [-f] [--fqdn] [-i] [--ip-address] [--long] [-s] [--short] [-y] [--yp] [--nis] [-n] [--node]

hostname [-v] [-F filename] [--file filename] [hostname]

hostname [-v] [-h] [--help] [-V] [--version]

Hostname is the program that is used to either set or display the current host, domain or node name of the system. These names are used by many of the networking programs to identify the machine. The domain name is also used by NIS/YP.

GET NAME

When called without any arguments, the program displays the current names:

hostname will print the name of the system as returned by the gethostname(2) function.

The function gethostname(2) is used to get the hostname. Only when the hostname -s is called will gethostbyname(3) be called. The difference in gethostname(2) and gethostbyname(3) is that gethostbyname(3) is network aware, so it consults /etc/nsswitch.conf and /etc/host.conf to decide whether to read information in /etc/sysconfig/network or /etc/hosts the hostname is also set when the network interface is brought up.

SET NAME

When called with one argument or with the --file option, the commands set the host name, the NIS/YP domain name or the node name.

Note, that only the super-user can change the names.

It is not possible to set the FQDN or the DNS domain name with the dnsdomainname command (see THE FQDN below).

The host name is usually set once at system startup in /etc/rc.d/rc.inet1 or /etc/init.d/boot (normally by reading the contents of a file which contains the host name, e.g. /etc/hostname).

THE FQDN

You can't change the FQDN (as returned by hostname --fqdn) or the DNS domain name (as returned by dnsdomainname) with this command. The FQDN of the system is the name that the resolver(3) returns for the host name.

Technically: The FQDN is the name gethostbyname(2) returns for the host name returned by gethostname(2). The DNS domain name is the part after the first dot.

Therefore it depends on the configuration (usually in /etc/host.conf) how you can change it. Usually (if the hosts file is parsed before DNS or NIS) you can change it in /etc/hosts.

Options

-a, --alias

Display the alias name of the host (if used).
-d, --domain
Display the name of the DNS domain. Don't use the command domainname to get the DNS domain name because it will show the NIS domain name and not the DNS domain name. Use dnsdomainname instead.
-F, --file filename
Read the host name from the specified file. Comments (lines starting with a '#') are ignored.
-f, --fqdn, --long
Display the FQDN (Fully Qualified Domain Name). A FQDN consists of a short host name and the DNS domain name. Unless you are using bind or NIS for host lookups you can change the FQDN and the DNS domain name (which is part of the FQDN) in the /etc/hosts file.
-h, --help
Print a usage message and exit.
-i, --ip-address
Display the IP address(es) of the host.
-s, --short
Display the short host name. This is the host name cut at the first dot.
-V, --version
Print version information on standard output and exit successfully.
-v, --verbose
Be verbose and tell what's going on.
-y, --yp, --nis
Display the NIS domain name. If a parameter is given (or --file name ) then root can also set a new NIS domain.

Recommended Links

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Top articles

Sites

hostname(1) show-set system's host name - Linux man page

Hostname - Wikipedia, the free encyclopedia

Domain Information Groper - Wikipedia, the free encyclopedia

nslookup - Wikipedia, the free encyclopedia

 



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Created May 16, 1996; Last modified: March 12, 2019