Feb 23, 2021

Mapping the chain of DNS servers from root to authoritative with dig

Key Points

The Domain Name System (DNS) turns domain names (jasonmurray.org) into IP addresses (104.21.41.57)
Root name servers point to servers that resolve top level domains like .com, .net, and .org
Second level name servers point to authoritative servers that resolve the second part of the domain such as jasonmurray, example, microsoft, and apple
Authoritative name servers resolve fully qualified domains such as jasonmurray.org, example.com, and microsoft.com
dig +trace jasonmurray.org displays the entire sequence of DNS servers required to resolve a domain name from root to authoratative

Overview

The dig +trace maps out all DNS servers required to resolve a DNS domain name. Typically only necessary when troubleshooting domain resolution issues. For curious minded individuals, this tool helps to explain the role each DNS server plays in name resolution.

Details

Trace all the DNS servers necessary to resolve the domain jasonmurray.org:

jemurray@shell:~$ dig +trace jasonmurray.org

; <<>> DiG 9.11.5-P4-5.1+deb10u2-Debian <<>> +trace jasonmurray.org
;; global options: +cmd
.			82734	IN	NS	a.root-servers.net.
.			82734	IN	NS	b.root-servers.net.
.			82734	IN	NS	c.root-servers.net.
.			82734	IN	NS	d.root-servers.net.
.			82734	IN	NS	e.root-servers.net.
.			82734	IN	NS	f.root-servers.net.
.			82734	IN	NS	g.root-servers.net.
.			82734	IN	NS	h.root-servers.net.
.			82734	IN	NS	i.root-servers.net.
.			82734	IN	NS	j.root-servers.net.
.			82734	IN	NS	k.root-servers.net.
.			82734	IN	NS	l.root-servers.net.
.			82734	IN	NS	m.root-servers.net.
.			82734	IN	RRSIG	NS 8 0 518400 20210221170000 20210208160000 42351 . JWnwNUp4kLm648L7JBzeiFOCM9ogRPM5zHTeNTuEYtmCvJoRxMzUcZ31 hf+M+hBr1/+qrjgvy11cRX/Zn/CuwgPAZKb0eMGQ59PqcqDrBwdSVCgA 8b5TQFHiv4Hc/72+ZgRsHghZyEAzGeBcfQuzw5QwW6mqowqmZV7nVb8o FEIf1rmM2WoQtvBQPQEdGFQDNGbaMgnXGieTKly1j8AOAs23UnH6Edih EA8fiSeqoLfowmqXdpdjfHxSWxbk8fgNUungDKPhoEhsr7xDzJfqUUtn t/XHo19nxn4icnEKaZOjMxCZwf193nsOpst8mHUFhIogRBhcuROVKpM+ lXm1BA==
;; Received 525 bytes from 2001:4860:4860::8844#53(2001:4860:4860::8844) in 2 ms

org.			172800	IN	NS	b0.org.afilias-nst.org.
org.			172800	IN	NS	a2.org.afilias-nst.info.
org.			172800	IN	NS	b2.org.afilias-nst.org.
org.			172800	IN	NS	c0.org.afilias-nst.info.
org.			172800	IN	NS	d0.org.afilias-nst.org.
org.			172800	IN	NS	a0.org.afilias-nst.info.
org.			86400	IN	DS	26974 8 2 4FEDE294C53F438A158C41D39489CD78A86BEB0D8A0AEAFF14745C0D 16E1DE32
org.			86400	IN	RRSIG	DS 8 1 86400 20210221170000 20210208160000 42351 . DVObWMq+MnZ994jALOhgw3dncWJ+BNZcawyCWQmD2iQkQOIURnQPLg++ DYOxhxOewokdxEPqNW773c1eSliEWobGlgpo9SbDPCGdTgQHRbE9cYVW G8y0quS8NHBKEeuv2ExF4JF/Q1M26koF7yTmpA6CgpWx4iAF2PcqDmx4 klwa9aXnuNX4gxVN8fUxXLJNEnXEov7/nEilkH03uoV/GVETbKEgtW9J fkB0XgaEUGSP3IZxYEpwNND4H2T9QvoFeg86qeO1YrvTiV8+CKn0PibF P8orSw05kPzTwye9r8E0CExD3+NUO29mCLa/ngqysiWSy2l2PeHUY8FK e2OaMg==
;; Received 809 bytes from 192.112.36.4#53(g.root-servers.net) in 31 ms

jasonmurray.org.	86400	IN	NS	dawn.ns.cloudflare.com.
jasonmurray.org.	86400	IN	NS	yisroel.ns.cloudflare.com.
jasonmurray.org.	86400	IN	DS	2371 13 2 DC7BAFCE4CE0D584175D5C87BC64790748AD3D701AB8B29B373702DD 7C9A0C77
jasonmurray.org.	86400	IN	RRSIG	DS 8 2 86400 20210222153204 20210201143204 34266 org. 0gaLcbBwh67NvGzheowXbEZfjk7gxzPF/VwWwCWHHV0LlWktiUuMXlYf VTwLyL8XHMtIM6HpPBkNlhY+gxRryJn9P12GQG4e18DAlMopv0fGf+yO fHHNc2dSHg+RyHRL1XaidLoRaQBnmoemR7tJ+wyInL8kw5zAGwASF5RQ fgM=
;; Received 313 bytes from 199.19.53.1#53(c0.org.afilias-nst.info) in 1 ms

jasonmurray.org.	300	IN	A	172.67.189.117
jasonmurray.org.	300	IN	A	104.21.41.57
jasonmurray.org.	300	IN	RRSIG	A 13 2 300 20210209224721 20210207204721 34505 jasonmurray.org. uP7iGuguXFNPA3ShGvMkCHp5SIIy9ARWOXhmCqg7EhS1AvS/OkqMbu8s Ui3cVu67Cw9govnw7BUd6gQoIAKaWA==
;; Received 187 bytes from 2803:f800:50::6ca2:c3b9#53(yisroel.ns.cloudflare.com) in 4 ms