How to: Check DNS Status of a Domain

In the process of administering an InterWorx server, it may be necessary to occasionally check the status of a DNS record, either against the server or other DNS servers. There are many websites that offer the ability to check DNS propagation, to examples being IntoDNS and WhatsMyDNS. However, very few services offer the wide range of options available in the dig command.

Using the dig command provides administrators with a powerful tool to check and confirm DNS records for their domains. More complete documentation can be found here: https://linux.die.net/man/1/dig or by running man dig on a Linux server. Below are a few examples of how to check DNS records with dig.

In the case where a public DNS record does not match the expected address of the record, it may be helpful to check the DNS against the InterWorx server to determine if it is showing the correct information.

Using dig to Check DNS Records

Most commands follow the format below, where type is the type of record to check (A, AAAA, CNAME, TXT, etc.), domain is the domain name to check, and server is the DNS server to check against:

dig type domain @server

The following examples use interworx.com as the domain.

  • To check interworx.com’s A record using upstream DNS servers:

    [root@iw7 ~]# dig a interworx.com +short
3.222.247.74
54.166.117.4
34.232.198.112

  • To check interworx.com’s A record using a specific DNS server. In this example, “ns1.interworx.com” is the domain of a specific nameserver. Replace this with the domain/IP address of the nameserver to check:

    [root@iw7 ~]# dig a interworx.com +short @ns1.interworx.com
10.1.14.83

  • If more verbose output is desired, removing +short will provide a more full list of the record:

    [root@iw7 ~]# dig a interworx.com

; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.3 <<>> a interworx.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54687
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;interworx.com.                   IN      A

;; ANSWER SECTION:
interworx.com.            59      IN      A       34.232.198.112
interworx.com.            59      IN      A       54.166.117.4
interworx.com.            59      IN      A       3.222.247.74

;; Query time: 18 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sun Feb 28 13:50:54 EST 2021
;; MSG SIZE  rcvd: 88