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DNS lookup

Everything DNS says about a domain: traced from the root servers down, every record type asked of the domain's own nameservers, each nameserver checked, then every hostname and policy record it points at followed, with SPF, DMARC, DKIM and DNSSEC checked along the way.

Try example.com, gmail.com, www.github.com, dnssec-failed.org, 1.1.1.1. A URL, e-mail address or IP address works too.

www.github.com

Zone github.com216 queries in 0.7 s2026-11-09 05:00:43 UTCNot DNSSEC-signed

WHOIS for github.com →TextJSON
  • Warning Nameservers disagree on the SOA serial (1656468023 on dns1.p08.nsone.net, dns2.p08.nsone.net, dns3.p08.nsone.net, dns4.p08.nsone.net; 1 on ns-1283.awsdns-32.org, ns-1707.awsdns-21.co.uk, ns-421.awsdns-52.com, ns-520.awsdns-01.net). Normal when two DNS providers serve the zone, each numbering its own copy; otherwise some servers haven't picked up the latest change.
  • Note github.com isn't signed with DNSSEC, so resolvers can't tell forged answers from real ones.

Records

Asked directly of ns-1283.awsdns-32.org (205.251.197.3), an authoritative server: no cache in between, so these are the live values.

CNAME Alias

3600CNAMEgithub.com.
ANY query: 1 records
3600CNAMEgithub.com.

No records of type A, AAAA, DNAME, NS, SOA, MX, TXT, CAA, HTTPS, SVCB, SRV, NAPTR, DS, DNSKEY, CDS, CDNSKEY, NSEC3PARAM, TLSA, SSHFP, LOC, HINFO, RP, URI, SPF, OPENPGPKEY, ZONEMD, CSYNC, PTR.

Resolution trace

  1. .asked c.root-servers.net 192.33.4.1243 ms

    Referral to com. signed (1 DS)

    • j.gtld-servers.net 192.48.79.30 2001:502:7094::30
    • e.gtld-servers.net 192.12.94.30 2001:502:1ca1::30
    • a.gtld-servers.net 192.5.6.30 2001:503:a83e::2:30
    • k.gtld-servers.net 192.52.178.30 2001:503:d2d::30
    • b.gtld-servers.net 192.33.14.30 2001:503:231d::2:30
    • i.gtld-servers.net 192.43.172.30 2001:503:39c1::30
    • l.gtld-servers.net 192.41.162.30 2001:500:d937::30
    • d.gtld-servers.net 192.31.80.30 2001:500:856e::30
    • h.gtld-servers.net 192.54.112.30 2001:502:8cc::30
    • m.gtld-servers.net 192.55.83.30 2001:501:b1f9::30
    • f.gtld-servers.net 192.35.51.30 2001:503:d414::30
    • c.gtld-servers.net 192.26.92.30 2001:503:83eb::30
    • g.gtld-servers.net 192.42.93.30 2001:503:eea3::30
  2. com.asked g.gtld-servers.net 192.42.93.3022 ms

    Referral to github.com. unsigned delegation

    • ns-520.awsdns-01.net 205.251.194.8 2600:9000:5302:800::1
    • ns-421.awsdns-52.com 205.251.193.165 2600:9000:5301:a500::1
    • ns-1707.awsdns-21.co.uk 205.251.198.171 2600:9000:5306:ab00::1
    • ns-1283.awsdns-32.org 205.251.197.3 2600:9000:5305:300::1
    • dns1.p08.nsone.net 198.51.44.8 2620:4d:4000:6259:7:8:0:1
    • dns2.p08.nsone.net 198.51.45.8 2a00:edc0:6259:7:8::2
    • dns3.p08.nsone.net 198.51.44.72 2620:4d:4000:6259:7:8:0:3
    • dns4.p08.nsone.net 198.51.45.72 2a00:edc0:6259:7:8::4

    No glue for ns-520.awsdns-01.net, ns-1707.awsdns-21.co.uk, ns-1283.awsdns-32.org, dns1.p08.nsone.net, dns2.p08.nsone.net, dns3.p08.nsone.net, dns4.p08.nsone.net: addresses looked up via a resolver.

    192.33.14.30 failed: NOERROR

  3. github.com.asked ns-520.awsdns-01.net 205.251.194.86.6 ms

    Alias:

    www.github.com.3600CNAMEgithub.com.

    198.51.45.72 failed: NOERROR

↳ which is an alias, so on to github.com, starting at the already known github.com. servers

  1. github.com.asked ns-1707.awsdns-21.co.uk 205.251.198.17111 ms

    Answer (authoritative):

    github.com.60A140.82.121.4

Nameservers

Every address of every nameserver, asked for github.com's SOA. "Parent" means the com zone delegates to it; "zone" means github.com lists it itself.

NameserverListed inAddressStatusSerialTime
dns1.p08.nsone.netparent + zone198.51.44.8 glueauthoritative165646802314 ms
2620:4d:4000:6259:7:8:0:1 glueauthoritative165646802315 ms
dns2.p08.nsone.netparent + zone198.51.45.8 glueauthoritative16564680235.8 ms
2a00:edc0:6259:7:8::2 glueauthoritative165646802313 ms
dns3.p08.nsone.netparent + zone198.51.44.72 glueauthoritative165646802314 ms
2620:4d:4000:6259:7:8:0:3 glueauthoritative165646802313 ms
dns4.p08.nsone.netparent + zone198.51.45.72 glueauthoritative16564680235.7 ms
2a00:edc0:6259:7:8::4 glueauthoritative165646802313 ms
ns-1283.awsdns-32.orgparent + zone205.251.197.3 glueauthoritative15.6 ms
2600:9000:5305:300::1 glueauthoritative16.2 ms
ns-1707.awsdns-21.co.ukparent + zone205.251.198.171 glueauthoritative112 ms
2600:9000:5306:ab00::1 glueauthoritative112 ms
ns-421.awsdns-52.comparent + zone205.251.193.165 glueauthoritative112 ms
2600:9000:5301:a500::1 glueauthoritative112 ms
ns-520.awsdns-01.netparent + zone205.251.194.8 glueauthoritative16.2 ms
2600:9000:5302:800::1 glueauthoritative16.8 ms

DNSSEC

github.com isn't signed: no DS at the parent and no DNSKEY in the zone.

Email

Mail servers (MX)

No MX records: mail goes to the name's A/AAAA address, if anything accepts it there.

SPF

No SPF record.

DMARC

v=DMARC1; p=quarantine; sp=reject; pct=100; rua=mailto:dmarc@github.com; ruf=mailto:dmarc@github.com; fo=1

From _dmarc.github.com (the organisational domain's policy applies).

Policyquarantine
Subdomain policyreject
Applies to100% of failing mail
Aggregate reports tomailto:dmarc@github.com
Failure reports tomailto:dmarc@github.com
Failure report options1

DKIM

None of the 36 common selectors tried has a key. DKIM may still be set up under another selector: find it in the DKIM-Signature header (s=) of a mail from this domain.

Hosts and reverse DNS

Every hostname the records point at, resolved to its addresses; each address's PTR (reverse DNS), with ✓ where the PTR name resolves back to the same address.

HostAddressReverse DNS (PTR)
www.github.com
the name looked up
→ github.com
140.82.121.3lb-140-82-121-3-fra.github.com ✓
github.com
CNAME target
140.82.121.4lb-140-82-121-4-fra.github.com ✓
dns1.p08.nsone.net
nameserver
198.51.44.8ns8.demysdns.com, dns1.p08.nsone.net ✓
2620:4d:4000:6259:7:8:0:1dns1.p08.nsone.net, ns8.demysdns.com ✓
dns2.p08.nsone.net
nameserver
198.51.45.8dns2.p08.nsone.net ✓
2a00:edc0:6259:7:8::2dns2.p08.nsone.net ✓
dns3.p08.nsone.net
nameserver
198.51.44.72dns3.p08.nsone.net ✓
2620:4d:4000:6259:7:8:0:3dns3.p08.nsone.net ✓
dns4.p08.nsone.net
nameserver
198.51.45.72dns4.p08.nsone.net ✓
2a00:edc0:6259:7:8::4dns4.p08.nsone.net ✓
ns-1283.awsdns-32.org
nameserver
205.251.197.3ns-1283.awsdns-32.org ✓
2600:9000:5305:300::1ns-1283.awsdns-32.org ✓
ns-1707.awsdns-21.co.uk
nameserver
205.251.198.171ns-1707.awsdns-21.co.uk ✓
2600:9000:5306:ab00::1ns-1707.awsdns-21.co.uk ✓
ns-421.awsdns-52.com
nameserver
205.251.193.165ns-421.awsdns-52.com ✓
2600:9000:5301:a500::1ns-421.awsdns-52.com ✓
ns-520.awsdns-01.net
nameserver
205.251.194.8ns-520.awsdns-01.net ✓
2600:9000:5302:800::1ns-520.awsdns-01.net ✓

Public resolvers

What four public resolvers answer right now, from their caches. Highlighted values differ from the authoritative answer: either a recent change they haven't picked up yet (the TTL says how long until they do), or, for A and AAAA, a CDN or geo-routed site handing each resolver location its own addresses.

ResolverAAAAAMX
Cloudflare 1.1.1.1140.82.121.3
TTL 60
none0 github-com.mail.protection.outlook.com.
TTL 300
Google 8.8.8.8140.82.121.3
TTL 60
none0 github-com.mail.protection.outlook.com.
TTL 269
Quad9 9.9.9.920.250.119.67
TTL 28
none0 github-com.mail.protection.outlook.com.
TTL 300
OpenDNS 208.67.222.22220.250.119.67
TTL 60
none0 github-com.mail.protection.outlook.com.
TTL 73

Text dump

; DNS report for www.github.com
; 2026-11-09 05:00:43 UTC, 216 queries in 0.74 s, zone github.com

;; FINDINGS
;  [WARN] Nameservers disagree on the SOA serial (1656468023 on dns1.p08.nsone.net, dns2.p08.nsone.net, dns3.p08.nsone.net, dns4.p08.nsone.net; 1 on ns-1283.awsdns-32.org, ns-1707.awsdns-21.co.uk, ns-421.awsdns-52.com, ns-520.awsdns-01.net). Normal when two DNS providers serve the zone, each numbering its own copy; otherwise some servers haven't picked up the latest change.
;  [INFO] github.com isn't signed with DNSSEC, so resolvers can't tell forged answers from real ones.

;; RECORDS (authoritative, from ns-1283.awsdns-32.org (205.251.197.3))
www.github.com.	3600	IN	CNAME	github.com.

;; TRACE
;  www.github.com A
;  . @c.root-servers.net (192.33.4.12) 43 ms [NOERROR qr]: referral to com.
com.		NS	j.gtld-servers.net.	; 192.48.79.30 2001:502:7094::30
com.		NS	e.gtld-servers.net.	; 192.12.94.30 2001:502:1ca1::30
com.		NS	a.gtld-servers.net.	; 192.5.6.30 2001:503:a83e::2:30
com.		NS	k.gtld-servers.net.	; 192.52.178.30 2001:503:d2d::30
com.		NS	b.gtld-servers.net.	; 192.33.14.30 2001:503:231d::2:30
com.		NS	i.gtld-servers.net.	; 192.43.172.30 2001:503:39c1::30
com.		NS	l.gtld-servers.net.	; 192.41.162.30 2001:500:d937::30
com.		NS	d.gtld-servers.net.	; 192.31.80.30 2001:500:856e::30
com.		NS	h.gtld-servers.net.	; 192.54.112.30 2001:502:8cc::30
com.		NS	m.gtld-servers.net.	; 192.55.83.30 2001:501:b1f9::30
com.		NS	f.gtld-servers.net.	; 192.35.51.30 2001:503:d414::30
com.		NS	c.gtld-servers.net.	; 192.26.92.30 2001:503:83eb::30
com.		NS	g.gtld-servers.net.	; 192.42.93.30 2001:503:eea3::30
com.	86400	IN	DS	19718 13 2 8ACBB0CD28F41250A80A491389424D341522D946B0DA0C0291F2D3D771D7805A
;  com. @g.gtld-servers.net (192.42.93.30) 22 ms [NOERROR qr]: referral to github.com.
github.com.		NS	ns-520.awsdns-01.net.	; 205.251.194.8 2600:9000:5302:800::1
github.com.		NS	ns-421.awsdns-52.com.	; 205.251.193.165 2600:9000:5301:a500::1
github.com.		NS	ns-1707.awsdns-21.co.uk.	; 205.251.198.171 2600:9000:5306:ab00::1
github.com.		NS	ns-1283.awsdns-32.org.	; 205.251.197.3 2600:9000:5305:300::1
github.com.		NS	dns1.p08.nsone.net.	; 198.51.44.8 2620:4d:4000:6259:7:8:0:1
github.com.		NS	dns2.p08.nsone.net.	; 198.51.45.8 2a00:edc0:6259:7:8::2
github.com.		NS	dns3.p08.nsone.net.	; 198.51.44.72 2620:4d:4000:6259:7:8:0:3
github.com.		NS	dns4.p08.nsone.net.	; 198.51.45.72 2a00:edc0:6259:7:8::4
;  github.com. @ns-520.awsdns-01.net (205.251.194.8) 6.6 ms [NOERROR qr aa ad]: alias
www.github.com.	3600	IN	CNAME	github.com.
;  github.com A
;  github.com. @ns-1707.awsdns-21.co.uk (205.251.198.171) 11 ms [NOERROR qr aa ad]: answer
github.com.	60	IN	A	140.82.121.4

;; NAMESERVERS (SOA asked of each address)
;  dns1.p08.nsone.net [parent+zone]
;    198.51.44.8                             ok                        1656468023  14 ms
;    2620:4d:4000:6259:7:8:0:1               ok                        1656468023  15 ms
;  dns2.p08.nsone.net [parent+zone]
;    198.51.45.8                             ok                        1656468023  5.8 ms
;    2a00:edc0:6259:7:8::2                   ok                        1656468023  13 ms
;  dns3.p08.nsone.net [parent+zone]
;    198.51.44.72                            ok                        1656468023  14 ms
;    2620:4d:4000:6259:7:8:0:3               ok                        1656468023  13 ms
;  dns4.p08.nsone.net [parent+zone]
;    198.51.45.72                            ok                        1656468023  5.7 ms
;    2a00:edc0:6259:7:8::4                   ok                        1656468023  13 ms
;  ns-1283.awsdns-32.org [parent+zone]
;    205.251.197.3                           ok                        1           5.6 ms
;    2600:9000:5305:300::1                   ok                        1           6.2 ms
;  ns-1707.awsdns-21.co.uk [parent+zone]
;    205.251.198.171                         ok                        1           12 ms
;    2600:9000:5306:ab00::1                  ok                        1           12 ms
;  ns-421.awsdns-52.com [parent+zone]
;    205.251.193.165                         ok                        1           12 ms
;    2600:9000:5301:a500::1                  ok                        1           12 ms
;  ns-520.awsdns-01.net [parent+zone]
;    205.251.194.8                           ok                        1           6.2 ms
;    2600:9000:5302:800::1                   ok                        1           6.8 ms

;; DNSSEC: unsigned

;; EMAIL
;  DMARC: v=DMARC1; p=quarantine; sp=reject; pct=100; rua=mailto:dmarc@github.com; ruf=mailto:dmarc@github.com; fo=1

;; RELATED NAMES
; ACME challenge delegation
_acme-challenge.www.github.com.	3600	IN	CNAME	www.github.com.acme.github.net.

;; HOSTS
;  www.github.com (the name looked up) -> github.com
;    140.82.121.3                            PTR lb-140-82-121-3-fra.github.com (confirmed)
;  github.com (CNAME target)
;    140.82.121.4                            PTR lb-140-82-121-4-fra.github.com (confirmed)
;  dns1.p08.nsone.net (nameserver)
;    198.51.44.8                             PTR ns8.demysdns.com, dns1.p08.nsone.net (confirmed)
;    2620:4d:4000:6259:7:8:0:1               PTR dns1.p08.nsone.net, ns8.demysdns.com (confirmed)
;  dns2.p08.nsone.net (nameserver)
;    198.51.45.8                             PTR dns2.p08.nsone.net (confirmed)
;    2a00:edc0:6259:7:8::2                   PTR dns2.p08.nsone.net (confirmed)
;  dns3.p08.nsone.net (nameserver)
;    198.51.44.72                            PTR dns3.p08.nsone.net (confirmed)
;    2620:4d:4000:6259:7:8:0:3               PTR dns3.p08.nsone.net (confirmed)
;  dns4.p08.nsone.net (nameserver)
;    198.51.45.72                            PTR dns4.p08.nsone.net (confirmed)
;    2a00:edc0:6259:7:8::4                   PTR dns4.p08.nsone.net (confirmed)
;  ns-1283.awsdns-32.org (nameserver)
;    205.251.197.3                           PTR ns-1283.awsdns-32.org (confirmed)
;    2600:9000:5305:300::1                   PTR ns-1283.awsdns-32.org (confirmed)
;  ns-1707.awsdns-21.co.uk (nameserver)
;    205.251.198.171                         PTR ns-1707.awsdns-21.co.uk (confirmed)
;    2600:9000:5306:ab00::1                  PTR ns-1707.awsdns-21.co.uk (confirmed)
;  ns-421.awsdns-52.com (nameserver)
;    205.251.193.165                         PTR ns-421.awsdns-52.com (confirmed)
;    2600:9000:5301:a500::1                  PTR ns-421.awsdns-52.com (confirmed)
;  ns-520.awsdns-01.net (nameserver)
;    205.251.194.8                           PTR ns-520.awsdns-01.net (confirmed)
;    2600:9000:5302:800::1                   PTR ns-520.awsdns-01.net (confirmed)

;; PUBLIC RESOLVERS
;  Cloudflare A     140.82.121.3  ttl 60
;  Cloudflare AAAA  -
;  Cloudflare MX    0 github-com.mail.protection.outlook.com.  ttl 300
;  Google     A     140.82.121.3  ttl 60
;  Google     AAAA  -
;  Google     MX    0 github-com.mail.protection.outlook.com.  ttl 269
;  Quad9      A     20.250.119.67  ttl 28
;  Quad9      AAAA  -
;  Quad9      MX    0 github-com.mail.protection.outlook.com.  ttl 300
;  OpenDNS    A     20.250.119.67  ttl 60
;  OpenDNS    AAAA  -
;  OpenDNS    MX    0 github-com.mail.protection.outlook.com.  ttl 73