> nslookup
> whois
The following sections briefly describe these tools and provide examples of their use.
dig
The Domain Information Groper is a command-line utility that queries DNS nameservers. By default, dig uses the nameservers listed in /etc/resolv.conf and performs an NS (nameserver) query. Reverse lookups are accomplished with the -x argument with a default A (Address) query.
Here is an example of a forward lookup with dig:
$ dig www.pearson.com
; <<>> DiG 9.5.0a6 <<>> www.pearson.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5889
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 3
;; QUESTION SECTION:
;www.pearson.com. IN A
;; ANSWER SECTION:
www.pearson.com. 86400 IN A 195.69.212.200
;; AUTHORITY SECTION:
pearson.com. 46430 IN NS ns2.pearson.com.
pearson.com. 46430 IN NS oldtxdns2.pearsontc.com.
pearson.com. 46430 IN NS ns.pearson.com.
;; ADDITIONAL SECTION:
ns.pearson.com. 162044 IN A 195.69.213.15
ns2.pearson.com. 78028 IN A 195.69.215.15
oldtxdns2.pearsontc.com. 139762 IN A 192.251.135.15
;; Query time: 50 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Sun Oct 28 20:02:53 2007
;; MSG SIZE rcvd: 166
And here is a reverse lookup with dig:
$ dig 195.69.212.200
; <<>> DiG 9.5.0a6 <<>> 195.69.212.200
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 53249
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;195.69.212.200. IN A
;; AUTHORITY SECTION:
. 10800 IN SOA A.ROOT-SERVERS.NET. NSTLD.VERISIGN-GRS.COM. 2007102800 1800 900 604800 86400
;; Query time: 47 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Sun Oct 28 20:03:49 2007
;; MSG SIZE rcvd: 107
host
A command-line utility, host performs forward and reverse lookups by querying DNS nameservers, similar to dig.
Here's an example of a forward lookup with host:
$ host www.pearson.com
www.pearson.com has address 195.69.212.200
Here's a reverse lookup with host:
$ host 195.69.212.200
200.212.69.195.in-addr.arpa domain name
pointer www.environment.pearson.com.
200.212.69.195.in-addr.arpa domain name
pointer booktime.pearson.com.
200.212.69.195.in-addr.arpa domain name
pointer environment.pearson.com.
nslookup
A command-line utility, nslookup can be used in an interactive or noninteractive manner to query DNS nameservers. Note that nslookup is outdated; try using dig instead.
Here's an example of a forward lookup using nslookup:
$ nslookup www.pearson.com
Server: 192.168.0.1
Address: 192.168.0.1#53
Non-authoritative answer:
Name: www.pearson.com Address: 195.69.212.200
Here's a reverse lookup using nslookup:
nslookup 195.69.212.200
Server: 192.168.2.1
Address: 192.168.2.1#53
Non-authoritative answer:
200.212.69.195.in-addr.arpa name = environment.pearson.com.
