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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.

140.82.121.4

4.121.82.140.in-addr.arpa

Zone 121.82.140.in-addr.arpa91 queries in 0.6 s2026-11-09 05:24:52 UTCNot DNSSEC-signed

WHOIS for 140.82.121.4 →TextJSON
  • Note 121.82.140.in-addr.arpa isn't signed with DNSSEC, so resolvers can't tell forged answers from real ones.

Records

Asked directly of dns2.p06.nsone.net (198.51.45.6), an authoritative server: no cache in between, so these are the live values.

PTR Reverse pointer

3600PTRlb-140-82-121-4-fra.github.com.
ANY query: refused politely (RFC 8482)
3600HINFO"RFC8482" ""

No records of type A, AAAA, CNAME, 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.

Resolution trace

  1. .asked e.root-servers.net 192.203.230.106.2 ms

    Referral to in-addr.arpa. signed (4 DS)

    • a.in-addr-servers.arpa 199.180.182.53 2620:37:e000::53
    • b.in-addr-servers.arpa 199.253.183.183 2001:500:87::87
    • c.in-addr-servers.arpa 196.216.169.10 2001:43f8:110::10
    • d.in-addr-servers.arpa 200.10.60.53 2001:13c7:7010::53
    • e.in-addr-servers.arpa 203.119.86.101 2001:dd8:6::101
    • f.in-addr-servers.arpa 193.0.9.1 2a13:27c0:30::1

    198.41.0.4 failed: NOERROR

  2. in-addr.arpa.asked a.in-addr-servers.arpa 199.180.182.5390 ms

    Referral to 140.in-addr.arpa. signed (1 DS)

    • y.arin.net 192.82.134.30 2001:500:127::30
    • x.arin.net 199.180.180.63 2001:500:f0::63
    • arin.authdns.ripe.net 193.0.9.10 2a13:27c0:30::10
    • r.arin.net 199.180.180.63 2001:500:f0::63
    • u.arin.net 204.61.216.50 2001:500:14:6050:ad::1
    • z.arin.net 199.180.180.63 2001:500:f0::63

    No glue for y.arin.net, x.arin.net, arin.authdns.ripe.net, r.arin.net, u.arin.net, z.arin.net: addresses looked up via a resolver.

  3. 140.in-addr.arpa.asked u.arin.net 204.61.216.505.7 ms

    Referral to 121.82.140.in-addr.arpa. unsigned delegation

    • dns2.p06.nsone.net 198.51.45.6 2a00:edc0:6259:7:6::2
    • dns1.p06.nsone.net 198.51.44.6 2620:4d:4000:6259:7:6:0:1
    • dns4.p06.nsone.net 198.51.45.70 2a00:edc0:6259:7:6::4
    • dns3.p06.nsone.net 198.51.44.70 2620:4d:4000:6259:7:6:0:3

    No glue for dns2.p06.nsone.net, dns1.p06.nsone.net, dns4.p06.nsone.net, dns3.p06.nsone.net: addresses looked up via a resolver.

  4. 121.82.140.in-addr.arpa.asked dns4.p06.nsone.net 198.51.45.706.1 ms

    Answer (authoritative):

    4.121.82.140.in-addr.arpa.3600PTRlb-140-82-121-4-fra.github.com.

    198.51.44.6 failed: NOERROR

Nameservers

Every address of every nameserver, asked for 121.82.140.in-addr.arpa's SOA. "Parent" means the 140.in-addr.arpa zone delegates to it; "zone" means 121.82.140.in-addr.arpa lists it itself.

NameserverListed inAddressStatusSerialTime
dns1.p06.nsone.netparent + zone198.51.44.6 glueauthoritative159894819213 ms
2620:4d:4000:6259:7:6:0:1 glueauthoritative159894819214 ms
dns2.p06.nsone.netparent + zone198.51.45.6 glueauthoritative15989481925.8 ms
2a00:edc0:6259:7:6::2 glueauthoritative159894819213 ms
dns3.p06.nsone.netparent + zone198.51.44.70 glueauthoritative159894819214 ms
2620:4d:4000:6259:7:6:0:3 glueauthoritative159894819213 ms
dns4.p06.nsone.netparent + zone198.51.45.70 glueauthoritative15989481925.9 ms
2a00:edc0:6259:7:6::4 glueauthoritative159894819212 ms

DNSSEC

121.82.140.in-addr.arpa isn't signed: no DS at the parent and no DNSKEY in the zone.

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)
dns1.p06.nsone.net
nameserver
198.51.44.6dns1.p06.nsone.net ✓
2620:4d:4000:6259:7:6:0:1dns1.p06.nsone.net ✓
dns2.p06.nsone.net
nameserver
198.51.45.6dns2.p06.nsone.net ✓
2a00:edc0:6259:7:6::2dns2.p06.nsone.net ✓
dns3.p06.nsone.net
nameserver
198.51.44.70dns3.p06.nsone.net ✓
2620:4d:4000:6259:7:6:0:3dns3.p06.nsone.net ✓
dns4.p06.nsone.net
nameserver
198.51.45.70dns4.p06.nsone.net ✓
2a00:edc0:6259:7:6::4dns4.p06.nsone.net ✓
lb-140-82-121-4-fra.github.com
PTR target
140.82.121.4lb-140-82-121-4-fra.github.com ✓

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.

ResolverPTR
Cloudflare 1.1.1.1lb-140-82-121-4-fra.github.com.
TTL 1171
Google 8.8.8.8lb-140-82-121-4-fra.github.com.
TTL 2707
Quad9 9.9.9.9lb-140-82-121-4-fra.github.com.
TTL 2773
OpenDNS 208.67.222.222lb-140-82-121-4-fra.github.com.
TTL 3114

Text dump

; DNS report for 4.121.82.140.in-addr.arpa (140.82.121.4)
; 2026-11-09 05:24:52 UTC, 91 queries in 0.58 s, zone 121.82.140.in-addr.arpa

;; FINDINGS
;  [INFO] 121.82.140.in-addr.arpa isn't signed with DNSSEC, so resolvers can't tell forged answers from real ones.

;; RECORDS (authoritative, from dns2.p06.nsone.net (198.51.45.6))
4.121.82.140.in-addr.arpa.	3600	IN	PTR	lb-140-82-121-4-fra.github.com.

;; TRACE
;  4.121.82.140.in-addr.arpa PTR
;  . @e.root-servers.net (192.203.230.10) 6.2 ms [NOERROR qr]: referral to in-addr.arpa.
in-addr.arpa.		NS	a.in-addr-servers.arpa.	; 199.180.182.53 2620:37:e000::53
in-addr.arpa.		NS	b.in-addr-servers.arpa.	; 199.253.183.183 2001:500:87::87
in-addr.arpa.		NS	c.in-addr-servers.arpa.	; 196.216.169.10 2001:43f8:110::10
in-addr.arpa.		NS	d.in-addr-servers.arpa.	; 200.10.60.53 2001:13c7:7010::53
in-addr.arpa.		NS	e.in-addr-servers.arpa.	; 203.119.86.101 2001:dd8:6::101
in-addr.arpa.		NS	f.in-addr-servers.arpa.	; 193.0.9.1 2a13:27c0:30::1
in-addr.arpa.	86400	IN	DS	47054 8 2 5CAFCCEC201D1933B4C9F6A9C8F51E51F3B39979058AC21B8DF1B1F281CBC6F2
in-addr.arpa.	86400	IN	DS	53696 8 2 13E5501C56B20394DA921B51412D48B7089C5EB6957A7C58553C4D4D424F04DF
in-addr.arpa.	86400	IN	DS	54956 8 2 E0E2BF5CFBD66572CA05EC18267D91509BA6A9405AF05C3FD4141DFA45200C08
in-addr.arpa.	86400	IN	DS	63982 8 2 AAF4FB5D213EF25AE44679032EBE3514C487D7ABD99D7F5FEC3383D030733C73
;  in-addr.arpa. @a.in-addr-servers.arpa (199.180.182.53) 90 ms [NOERROR qr]: referral to 140.in-addr.arpa.
140.in-addr.arpa.		NS	y.arin.net.	; 192.82.134.30 2001:500:127::30
140.in-addr.arpa.		NS	x.arin.net.	; 199.180.180.63 2001:500:f0::63
140.in-addr.arpa.		NS	arin.authdns.ripe.net.	; 193.0.9.10 2a13:27c0:30::10
140.in-addr.arpa.		NS	r.arin.net.	; 199.180.180.63 2001:500:f0::63
140.in-addr.arpa.		NS	u.arin.net.	; 204.61.216.50 2001:500:14:6050:ad::1
140.in-addr.arpa.		NS	z.arin.net.	; 199.180.180.63 2001:500:f0::63
140.in-addr.arpa.	86400	IN	DS	30527 8 2 45E06D6D1051D6E38BB7D0C7E81FBDE58C067F215395E4769F2DBCD5F6DA29B9
;  140.in-addr.arpa. @u.arin.net (204.61.216.50) 5.7 ms [NOERROR qr]: referral to 121.82.140.in-addr.arpa.
121.82.140.in-addr.arpa.		NS	dns2.p06.nsone.net.	; 198.51.45.6 2a00:edc0:6259:7:6::2
121.82.140.in-addr.arpa.		NS	dns1.p06.nsone.net.	; 198.51.44.6 2620:4d:4000:6259:7:6:0:1
121.82.140.in-addr.arpa.		NS	dns4.p06.nsone.net.	; 198.51.45.70 2a00:edc0:6259:7:6::4
121.82.140.in-addr.arpa.		NS	dns3.p06.nsone.net.	; 198.51.44.70 2620:4d:4000:6259:7:6:0:3
;  121.82.140.in-addr.arpa. @dns4.p06.nsone.net (198.51.45.70) 6.1 ms [NOERROR qr aa]: answer
4.121.82.140.in-addr.arpa.	3600	IN	PTR	lb-140-82-121-4-fra.github.com.

;; NAMESERVERS (SOA asked of each address)
;  dns1.p06.nsone.net [parent+zone]
;    198.51.44.6                             ok                        1598948192  13 ms
;    2620:4d:4000:6259:7:6:0:1               ok                        1598948192  14 ms
;  dns2.p06.nsone.net [parent+zone]
;    198.51.45.6                             ok                        1598948192  5.8 ms
;    2a00:edc0:6259:7:6::2                   ok                        1598948192  13 ms
;  dns3.p06.nsone.net [parent+zone]
;    198.51.44.70                            ok                        1598948192  14 ms
;    2620:4d:4000:6259:7:6:0:3               ok                        1598948192  13 ms
;  dns4.p06.nsone.net [parent+zone]
;    198.51.45.70                            ok                        1598948192  5.9 ms
;    2a00:edc0:6259:7:6::4                   ok                        1598948192  12 ms

;; DNSSEC: unsigned

;; HOSTS
;  dns1.p06.nsone.net (nameserver)
;    198.51.44.6                             PTR dns1.p06.nsone.net (confirmed)
;    2620:4d:4000:6259:7:6:0:1               PTR dns1.p06.nsone.net (confirmed)
;  dns2.p06.nsone.net (nameserver)
;    198.51.45.6                             PTR dns2.p06.nsone.net (confirmed)
;    2a00:edc0:6259:7:6::2                   PTR dns2.p06.nsone.net (confirmed)
;  dns3.p06.nsone.net (nameserver)
;    198.51.44.70                            PTR dns3.p06.nsone.net (confirmed)
;    2620:4d:4000:6259:7:6:0:3               PTR dns3.p06.nsone.net (confirmed)
;  dns4.p06.nsone.net (nameserver)
;    198.51.45.70                            PTR dns4.p06.nsone.net (confirmed)
;    2a00:edc0:6259:7:6::4                   PTR dns4.p06.nsone.net (confirmed)
;  lb-140-82-121-4-fra.github.com (PTR target)
;    140.82.121.4                            PTR lb-140-82-121-4-fra.github.com (confirmed)

;; PUBLIC RESOLVERS
;  Cloudflare PTR   lb-140-82-121-4-fra.github.com.  ttl 1171
;  Google     PTR   lb-140-82-121-4-fra.github.com.  ttl 2707
;  Quad9      PTR   lb-140-82-121-4-fra.github.com.  ttl 2773
;  OpenDNS    PTR   lb-140-82-121-4-fra.github.com.  ttl 3114