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.

205.251.197.105

105.197.251.205.in-addr.arpa

Zone 197.251.205.in-addr.arpa129 queries in 1.0 s2026-11-09 05:55:10 UTCNot DNSSEC-signed

WHOIS for 205.251.197.105 →Text JSON

Warning Nameservers disagree on the SOA serial (1 on ns-1293.awsdns-33.org, ns-2044.awsdns-63.co.uk, ns-726.awsdns-26.net, ns-74.awsdns-09.com; 4 on pdns1.ultradns.net, x1.amazonaws.com, x2.amazonaws.com, x3.amazonaws.org, x4.amazonaws.org). Normal when two DNS providers serve the zone, each numbering its own copy; otherwise some servers haven't picked up the latest change.
Warning The parent zone delegates to pdns1.ultradns.net, x1.amazonaws.com, x2.amazonaws.com, x3.amazonaws.org, x4.amazonaws.org but 197.251.205.in-addr.arpa itself lists ns-1293.awsdns-33.org, ns-2044.awsdns-63.co.uk, ns-726.awsdns-26.net, ns-74.awsdns-09.com. Make the two lists match.
Note 197.251.205.in-addr.arpa isn't signed with DNSSEC, so resolvers can't tell forged answers from real ones.

Records

Asked directly of ns-1293.awsdns-33.org (205.251.197.13), an authoritative server: no cache in between, so these are the live values.

PTR Reverse pointer

172800

PTR

ns-1385.awsdns-45.org.

ANY query: 1 records

172800

PTR

ns-1385.awsdns-45.org.

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

.asked d.root-servers.net 199.7.91.135.8 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
192.33.4.12 failed: NOERROR
in-addr.arpa.asked a.in-addr-servers.arpa 199.180.182.5390 ms
Referral to 205.in-addr.arpa. signed (1 DS)
- z.arin.net 199.180.180.63 2001:500:f0::63
- y.arin.net 192.82.134.30 2001:500:127::30
- r.arin.net 199.180.180.63 2001:500:f0::63
- x.arin.net 199.180.180.63 2001:500:f0::63
- u.arin.net 204.61.216.50 2001:500:14:6050:ad::1
- arin.authdns.ripe.net 193.0.9.10 2a13:27c0:30::10
No glue for z.arin.net, y.arin.net, r.arin.net, x.arin.net, u.arin.net, arin.authdns.ripe.net: addresses looked up via a resolver.
205.in-addr.arpa.asked u.arin.net 204.61.216.505.5 ms
Referral to 197.251.205.in-addr.arpa. unsigned delegation
- x4.amazonaws.org 204.74.120.1
- x3.amazonaws.org 156.154.150.1
- x2.amazonaws.com 156.154.65.10
- pdns1.ultradns.net 204.74.108.1 2001:502:f3ff::1
- x1.amazonaws.com 156.154.64.10
No glue for x4.amazonaws.org, x3.amazonaws.org, x2.amazonaws.com, pdns1.ultradns.net, x1.amazonaws.com: addresses looked up via a resolver.
197.251.205.in-addr.arpa.asked x2.amazonaws.com 156.154.65.105.5 ms
Answer (authoritative):
105.197.251.205.in-addr.arpa. 172800 PTR ns-1385.awsdns-45.org.
156.154.150.1 failed: NOERROR

Nameservers

Every address of every nameserver, asked for 197.251.205.in-addr.arpa's SOA. "Parent" means the 205.in-addr.arpa zone delegates to it; "zone" means 197.251.205.in-addr.arpa lists it itself.

Nameserver

Listed in

Address

Status

Serial

Time

ns-1293.awsdns-33.org

zone

205.251.197.13

authoritative

5.6 ms

2600:9000:5305:d00::1

authoritative

5.7 ms

ns-2044.awsdns-63.co.uk

zone

205.251.199.252

authoritative

11 ms

2600:9000:5307:fc00::1

authoritative

11 ms

ns-726.awsdns-26.net

zone

205.251.194.214

authoritative

5.7 ms

2600:9000:5302:d600::1

authoritative

5.9 ms

ns-74.awsdns-09.com

zone

205.251.192.74

authoritative

11 ms

2600:9000:5300:4a00::1

authoritative

11 ms

pdns1.ultradns.net

parent

204.74.108.1 glue

authoritative

5.7 ms

2001:502:f3ff::1 glue

authoritative

5.8 ms

x1.amazonaws.com

parent

156.154.64.10 glue

authoritative

5.7 ms

x2.amazonaws.com

parent

156.154.65.10 glue

authoritative

5.9 ms

x3.amazonaws.org

parent

156.154.150.1 glue

authoritative

6.5 ms

x4.amazonaws.org

parent

204.74.120.1 glue

authoritative

17 ms

DNSSEC

197.251.205.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.

Host

Address

Reverse DNS (PTR)

ns-1293.awsdns-33.org

nameserver

205.251.197.13

ns-1293.awsdns-33.org ✓

2600:9000:5305:d00::1

ns-1293.awsdns-33.org ✓

ns-2044.awsdns-63.co.uk

nameserver

205.251.199.252

ns-2044.awsdns-63.co.uk ✓

2600:9000:5307:fc00::1

ns-2044.awsdns-63.co.uk ✓

ns-726.awsdns-26.net

nameserver

205.251.194.214

ns-726.awsdns-26.net ✓

2600:9000:5302:d600::1

ns-726.awsdns-26.net ✓

ns-74.awsdns-09.com

nameserver

205.251.192.74

ns-74.awsdns-09.com ✓

2600:9000:5300:4a00::1

ns-74.awsdns-09.com ✓

pdns1.ultradns.net

nameserver

204.74.108.1

pdns1.ultradns.net ✓

2001:502:f3ff::1

pdns1.ultradns.net ✓

x1.amazonaws.com

nameserver

156.154.64.10

u1.amazonaws.com ✓

x2.amazonaws.com

nameserver

156.154.65.10

u2.amazonaws.com ✓

x3.amazonaws.org

nameserver

156.154.150.1

dns-01.ultradns2.com ✓

x4.amazonaws.org

nameserver

204.74.120.1

dns-01.ultradns2.org ✓

ns-1385.awsdns-45.org

PTR target

205.251.197.105

ns-1385.awsdns-45.org ✓

2600:9000:5305:6900::1

ns-1385.awsdns-45.org ✓

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.

Resolver

PTR

Cloudflare 1.1.1.1

ns-1385.awsdns-45.org.

TTL 172800

Google 8.8.8.8

ns-1385.awsdns-45.org.

TTL 20456

Quad9 9.9.9.9

ns-1385.awsdns-45.org.

TTL 43200

OpenDNS 208.67.222.222

ns-1385.awsdns-45.org.

TTL 172800

Text dump

; DNS report for 105.197.251.205.in-addr.arpa (205.251.197.105)
; 2026-11-09 05:55:10 UTC, 129 queries in 1.02 s, zone 197.251.205.in-addr.arpa

;; FINDINGS
;  [WARN] Nameservers disagree on the SOA serial (1 on ns-1293.awsdns-33.org, ns-2044.awsdns-63.co.uk, ns-726.awsdns-26.net, ns-74.awsdns-09.com; 4 on pdns1.ultradns.net, x1.amazonaws.com, x2.amazonaws.com, x3.amazonaws.org, x4.amazonaws.org). Normal when two DNS providers serve the zone, each numbering its own copy; otherwise some servers haven't picked up the latest change.
;  [WARN] The parent zone delegates to pdns1.ultradns.net, x1.amazonaws.com, x2.amazonaws.com, x3.amazonaws.org, x4.amazonaws.org but 197.251.205.in-addr.arpa itself lists ns-1293.awsdns-33.org, ns-2044.awsdns-63.co.uk, ns-726.awsdns-26.net, ns-74.awsdns-09.com. Make the two lists match.
;  [INFO] 197.251.205.in-addr.arpa isn't signed with DNSSEC, so resolvers can't tell forged answers from real ones.

;; RECORDS (authoritative, from ns-1293.awsdns-33.org (205.251.197.13))
105.197.251.205.in-addr.arpa.	172800	IN	PTR	ns-1385.awsdns-45.org.

;; TRACE
;  105.197.251.205.in-addr.arpa PTR
;  . @d.root-servers.net (199.7.91.13) 5.8 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 205.in-addr.arpa.
205.in-addr.arpa.		NS	z.arin.net.	; 199.180.180.63 2001:500:f0::63
205.in-addr.arpa.		NS	y.arin.net.	; 192.82.134.30 2001:500:127::30
205.in-addr.arpa.		NS	r.arin.net.	; 199.180.180.63 2001:500:f0::63
205.in-addr.arpa.		NS	x.arin.net.	; 199.180.180.63 2001:500:f0::63
205.in-addr.arpa.		NS	u.arin.net.	; 204.61.216.50 2001:500:14:6050:ad::1
205.in-addr.arpa.		NS	arin.authdns.ripe.net.	; 193.0.9.10 2a13:27c0:30::10
205.in-addr.arpa.	86400	IN	DS	37219 8 2 8995F93F2EFA4E23997F6A7E3455F1E9A7C20A10A346FDF5A89AA1775664EFF9
;  205.in-addr.arpa. @u.arin.net (204.61.216.50) 5.5 ms [NOERROR qr]: referral to 197.251.205.in-addr.arpa.
197.251.205.in-addr.arpa.		NS	x4.amazonaws.org.	; 204.74.120.1
197.251.205.in-addr.arpa.		NS	x3.amazonaws.org.	; 156.154.150.1
197.251.205.in-addr.arpa.		NS	x2.amazonaws.com.	; 156.154.65.10
197.251.205.in-addr.arpa.		NS	pdns1.ultradns.net.	; 204.74.108.1 2001:502:f3ff::1
197.251.205.in-addr.arpa.		NS	x1.amazonaws.com.	; 156.154.64.10
;  197.251.205.in-addr.arpa. @x2.amazonaws.com (156.154.65.10) 5.5 ms [NOERROR qr aa]: answer
105.197.251.205.in-addr.arpa.	172800	IN	PTR	ns-1385.awsdns-45.org.

;; NAMESERVERS (SOA asked of each address)
;  ns-1293.awsdns-33.org [zone]
;    205.251.197.13                          ok                        1           5.6 ms
;    2600:9000:5305:d00::1                   ok                        1           5.7 ms
;  ns-2044.awsdns-63.co.uk [zone]
;    205.251.199.252                         ok                        1           11 ms
;    2600:9000:5307:fc00::1                  ok                        1           11 ms
;  ns-726.awsdns-26.net [zone]
;    205.251.194.214                         ok                        1           5.7 ms
;    2600:9000:5302:d600::1                  ok                        1           5.9 ms
;  ns-74.awsdns-09.com [zone]
;    205.251.192.74                          ok                        1           11 ms
;    2600:9000:5300:4a00::1                  ok                        1           11 ms
;  pdns1.ultradns.net [parent]
;    204.74.108.1                            ok                        4           5.7 ms
;    2001:502:f3ff::1                        ok                        4           5.8 ms
;  x1.amazonaws.com [parent]
;    156.154.64.10                           ok                        4           5.7 ms
;  x2.amazonaws.com [parent]
;    156.154.65.10                           ok                        4           5.9 ms
;  x3.amazonaws.org [parent]
;    156.154.150.1                           ok                        4           6.5 ms
;  x4.amazonaws.org [parent]
;    204.74.120.1                            ok                        4           17 ms

;; DNSSEC: unsigned

;; HOSTS
;  ns-1293.awsdns-33.org (nameserver)
;    205.251.197.13                          PTR ns-1293.awsdns-33.org (confirmed)
;    2600:9000:5305:d00::1                   PTR ns-1293.awsdns-33.org (confirmed)
;  ns-2044.awsdns-63.co.uk (nameserver)
;    205.251.199.252                         PTR ns-2044.awsdns-63.co.uk (confirmed)
;    2600:9000:5307:fc00::1                  PTR ns-2044.awsdns-63.co.uk (confirmed)
;  ns-726.awsdns-26.net (nameserver)
;    205.251.194.214                         PTR ns-726.awsdns-26.net (confirmed)
;    2600:9000:5302:d600::1                  PTR ns-726.awsdns-26.net (confirmed)
;  ns-74.awsdns-09.com (nameserver)
;    205.251.192.74                          PTR ns-74.awsdns-09.com (confirmed)
;    2600:9000:5300:4a00::1                  PTR ns-74.awsdns-09.com (confirmed)
;  pdns1.ultradns.net (nameserver)
;    204.74.108.1                            PTR pdns1.ultradns.net (confirmed)
;    2001:502:f3ff::1                        PTR pdns1.ultradns.net (confirmed)
;  x1.amazonaws.com (nameserver)
;    156.154.64.10                           PTR u1.amazonaws.com (confirmed)
;  x2.amazonaws.com (nameserver)
;    156.154.65.10                           PTR u2.amazonaws.com (confirmed)
;  x3.amazonaws.org (nameserver)
;    156.154.150.1                           PTR dns-01.ultradns2.com (confirmed)
;  x4.amazonaws.org (nameserver)
;    204.74.120.1                            PTR dns-01.ultradns2.org (confirmed)
;  ns-1385.awsdns-45.org (PTR target)
;    205.251.197.105                         PTR ns-1385.awsdns-45.org (confirmed)
;    2600:9000:5305:6900::1                  PTR ns-1385.awsdns-45.org (confirmed)

;; PUBLIC RESOLVERS
;  Cloudflare PTR   ns-1385.awsdns-45.org.  ttl 172800
;  Google     PTR   ns-1385.awsdns-45.org.  ttl 20456
;  Quad9      PTR   ns-1385.awsdns-45.org.  ttl 43200
;  OpenDNS    PTR   ns-1385.awsdns-45.org.  ttl 172800