The DNS service is often one of the most overlooked services when analysing website problems. Developers often focus on the webservices, and they forget about the DNS servers, that play a crucial role while troubleshooting website & email errors.
What is a DNS Check? Do I need one for my website?
A dns check, also known as dns report, is just a anlaysys of your DNS servers. This is done by using automated tools like dnslog.com
DNS checkers will analyze each and everyone of the aspect of your DNS servers, including A, CNAME, MX and TXT records. This tools can give you great suggestions on how to improve your DNS & mail health.
A DNS Report tool run a complete DNS test for the specified domains, and then analize all your records looking for performance, configuration and security errors.
Alternative ways to run a DNS Test
Tools like the one we mentioned are often the best way to test your DNS servers, however, if you have deep knowledge of the dns system and how it works, you can also use our beloved dig command or nslookup to analyze your dns & mail configuration.
For example, if we need to know the confiiguration of our main A record, we would end up using this command.
dig A nixcp.com
This should be the output:
[webtech@localhost ~]$ dig A nixcp.com ; <<>> DiG 9.10.4-P6-RedHat-9.10.4-4.P6.fc25 <<>> A nixcp.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27496 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 7 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;nixcp.com. IN A ;; ANSWER SECTION: nixcp.com. 841 IN A 66.55.147.204 ;; AUTHORITY SECTION: nixcp.com. 85441 IN NS ns3.dnsmadeeasy.com. nixcp.com. 85441 IN NS ns4.dnsmadeeasy.com. nixcp.com. 85441 IN NS ns2.dnsmadeeasy.com. nixcp.com. 85441 IN NS ns0.dnsmadeeasy.com. ;; ADDITIONAL SECTION: ns0.dnsmadeeasy.com. 82373 IN A 208.94.148.2 ns2.dnsmadeeasy.com. 86126 IN A 208.80.126.2 ns3.dnsmadeeasy.com. 83493 IN A 208.80.125.2 ns3.dnsmadeeasy.com. 84921 IN AAAA 2600:1801:3::1 ns4.dnsmadeeasy.com. 86055 IN A 208.80.127.2 ns4.dnsmadeeasy.com. 79930 IN AAAA 2600:1802:4::1 ;; Query time: 6 msec ;; SERVER: 192.168.1.1#53(192.168.1.1) ;; WHEN: Fri Apr 21 08:18:49 -03 2017 ;; MSG SIZE rcvd: 263 [webtech@localhost ~]$
From there you can analyze the records, of course you will have to know all (or the most important ones) the DNS rules and specifications by the IETF organization.