17.2.4. Using the dig Utility The dig utility is a command-line tool that allows you to perform DNS lookups and debug a nameserver configuration. Its typical usage is as follows: See Section 17.2.2.2, "Common Resource Records" for a list of common type s. 17.2.4.1. Looking Up a Nameserver To look up a nameserver for a particular domain, use the command in the following form: In Example 17.17, "A sample nameserver lookup" , the dig utility is used to display nameservers for example.com . Example 17.17. A sample nameserver lookup 17.2.4.2. Looking Up an IP Address To look up an IP address assigned to a particular domain, use the command in the following form: In Example 17.18, "A sample IP address lookup" , the dig utility is used to display the IP address of example.com . Example 17.18. A sample IP address lookup 17.2.4.3. Looking Up a Hostname To look up a host name for a particular IP address, use the command in the following form: In Example 17.19, "A sample host name lookup" , the dig utility is used to display the host name assigned to 192.0.32.10 . Example 17.19. A sample host name lookup

Commands:
dig [@ server ] [ option ...] name type
dig name NS
~]USD dig example.com NS ; <<>> DiG 9.7.1-P2-RedHat-9.7.1-2.P2.fc13 <<>> example.com NS ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57883 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;example.com. IN NS ;; ANSWER SECTION: example.com. 99374 IN NS a.iana-servers.net. example.com. 99374 IN NS b.iana-servers.net. ;; Query time: 1 msec ;; SERVER: 10.34.255.7#53(10.34.255.7) ;; WHEN: Wed Aug 18 18:04:06 2010 ;; MSG SIZE rcvd: 77
dig name A
~]USD dig example.com A ; <<>> DiG 9.7.1-P2-RedHat-9.7.1-2.P2.fc13 <<>> example.com A ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4849 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0 ;; QUESTION SECTION: ;example.com. IN A ;; ANSWER SECTION: example.com. 155606 IN A 192.0.32.10 ;; AUTHORITY SECTION: example.com. 99175 IN NS a.iana-servers.net. example.com. 99175 IN NS b.iana-servers.net. ;; Query time: 1 msec ;; SERVER: 10.34.255.7#53(10.34.255.7) ;; WHEN: Wed Aug 18 18:07:25 2010 ;; MSG SIZE rcvd: 93
dig -x address
~]USD dig -x 192.0.32.10 ; <<>> DiG 9.7.1-P2-RedHat-9.7.1-2.P2.fc13 <<>> -x 192.0.32.10 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29683 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 6 ;; QUESTION SECTION: ;10.32.0.192.in-addr.arpa. IN PTR ;; ANSWER SECTION: 10.32.0.192.in-addr.arpa. 21600 IN PTR www.example.com. ;; AUTHORITY SECTION: 32.0.192.in-addr.arpa. 21600 IN NS b.iana-servers.org. 32.0.192.in-addr.arpa. 21600 IN NS c.iana-servers.net. 32.0.192.in-addr.arpa. 21600 IN NS d.iana-servers.net. 32.0.192.in-addr.arpa. 21600 IN NS ns.icann.org. 32.0.192.in-addr.arpa. 21600 IN NS a.iana-servers.net. ;; ADDITIONAL SECTION: a.iana-servers.net. 13688 IN A 192.0.34.43 b.iana-servers.org. 5844 IN A 193.0.0.236 b.iana-servers.org. 5844 IN AAAA 2001:610:240:2::c100:ec c.iana-servers.net. 12173 IN A 139.91.1.10 c.iana-servers.net. 12173 IN AAAA 2001:648:2c30::1:10 ns.icann.org. 12884 IN A 192.0.34.126 ;; Query time: 156 msec ;; SERVER: 10.34.255.7#53(10.34.255.7) ;; WHEN: Wed Aug 18 18:25:15 2010 ;; MSG SIZE rcvd: 310