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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.

205.251.194.243

243.194.251.205.in-addr.arpa

Zone 194.251.205.in-addr.arpa129 queries in 0.5 s2026-11-09 05:55:07 UTCNot DNSSEC-signed

WHOIS for 205.251.194.243 →TextJSON
  • Warning Nameservers disagree on the SOA serial (1 on ns-1184.awsdns-20.org, ns-1841.awsdns-38.co.uk, ns-458.awsdns-57.com, ns-620.awsdns-13.net; 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 194.251.205.in-addr.arpa itself lists ns-1184.awsdns-20.org, ns-1841.awsdns-38.co.uk, ns-458.awsdns-57.com, ns-620.awsdns-13.net. Make the two lists match.
  • Note 194.251.205.in-addr.arpa isn't signed with DNSSEC, so resolvers can't tell forged answers from real ones.

Records

Asked directly of ns-1184.awsdns-20.org (205.251.196.160), an authoritative server: no cache in between, so these are the live values.

PTR Reverse pointer

172800PTRns-755.awsdns-30.net.
ANY query: 1 records
172800PTRns-755.awsdns-30.net.

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 k.root-servers.net 193.0.14.12938 ms

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

    • f.in-addr-servers.arpa 193.0.9.1 2a13:27c0:30::1
    • e.in-addr-servers.arpa 203.119.86.101 2001:dd8:6::101
    • a.in-addr-servers.arpa 199.180.182.53 2620:37:e000::53
    • 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
    • b.in-addr-servers.arpa 199.253.183.183 2001:500:87::87

    192.33.4.12 failed: NOERROR

  2. in-addr.arpa.asked a.in-addr-servers.arpa 199.180.182.5393 ms

    Referral to 205.in-addr.arpa. signed (1 DS)

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

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

    200.10.60.53 failed: NOERROR

  3. 205.in-addr.arpa.asked y.arin.net 192.82.134.306.3 ms

    Referral to 194.251.205.in-addr.arpa. unsigned delegation

    • x3.amazonaws.org 156.154.150.1
    • pdns1.ultradns.net 204.74.108.1 2001:502:f3ff::1
    • x1.amazonaws.com 156.154.64.10
    • x2.amazonaws.com 156.154.65.10
    • x4.amazonaws.org 204.74.120.1

    No glue for x3.amazonaws.org, pdns1.ultradns.net, x1.amazonaws.com, x2.amazonaws.com, x4.amazonaws.org: addresses looked up via a resolver.

    199.180.180.63 failed: NOERROR

  4. 194.251.205.in-addr.arpa.asked x1.amazonaws.com 156.154.64.105.7 ms

    Answer (authoritative):

    243.194.251.205.in-addr.arpa.172800PTRns-755.awsdns-30.net.

Nameservers

Every address of every nameserver, asked for 194.251.205.in-addr.arpa's SOA. "Parent" means the 205.in-addr.arpa zone delegates to it; "zone" means 194.251.205.in-addr.arpa lists it itself.

NameserverListed inAddressStatusSerialTime
ns-1184.awsdns-20.orgzone205.251.196.160authoritative15.4 ms
2600:9000:5304:a000::1authoritative18.0 ms
ns-1841.awsdns-38.co.ukzone205.251.199.49authoritative111 ms
2600:9000:5307:3100::1authoritative114 ms
ns-458.awsdns-57.comzone205.251.193.202authoritative111 ms
2600:9000:5301:ca00::1authoritative114 ms
ns-620.awsdns-13.netzone205.251.194.108authoritative16.1 ms
2600:9000:5302:6c00::1authoritative18.7 ms
pdns1.ultradns.netparent204.74.108.1 glueauthoritative45.8 ms
2001:502:f3ff::1 glueauthoritative46.1 ms
x1.amazonaws.comparent156.154.64.10 glueauthoritative46.1 ms
x2.amazonaws.comparent156.154.65.10 glueauthoritative46.1 ms
x3.amazonaws.orgparent156.154.150.1 glueauthoritative46.5 ms
x4.amazonaws.orgparent204.74.120.1 glueauthoritative417 ms

DNSSEC

194.251.205.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.

HostAddressReverse DNS (PTR)
ns-1184.awsdns-20.org
nameserver
205.251.196.160ns-1184.awsdns-20.org ✓
2600:9000:5304:a000::1ns-1184.awsdns-20.org ✓
ns-1841.awsdns-38.co.uk
nameserver
205.251.199.49ns-1841.awsdns-38.co.uk ✓
2600:9000:5307:3100::1ns-1841.awsdns-38.co.uk ✓
ns-458.awsdns-57.com
nameserver
205.251.193.202ns-458.awsdns-57.com ✓
2600:9000:5301:ca00::1ns-458.awsdns-57.com ✓
ns-620.awsdns-13.net
nameserver
205.251.194.108ns-620.awsdns-13.net ✓
2600:9000:5302:6c00::1ns-620.awsdns-13.net ✓
pdns1.ultradns.net
nameserver
204.74.108.1pdns1.ultradns.net ✓
2001:502:f3ff::1pdns1.ultradns.net ✓
x1.amazonaws.com
nameserver
156.154.64.10u1.amazonaws.com ✓
x2.amazonaws.com
nameserver
156.154.65.10u2.amazonaws.com ✓
x3.amazonaws.org
nameserver
156.154.150.1dns-01.ultradns2.com ✓
x4.amazonaws.org
nameserver
204.74.120.1dns-01.ultradns2.org ✓
ns-755.awsdns-30.net
PTR target
205.251.194.243ns-755.awsdns-30.net ✓
2600:9000:5302:f300::1ns-755.awsdns-30.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.

ResolverPTR
Cloudflare 1.1.1.1ns-755.awsdns-30.net.
TTL 172800
Google 8.8.8.8ns-755.awsdns-30.net.
TTL 21600
Quad9 9.9.9.9ns-755.awsdns-30.net.
TTL 43200
OpenDNS 208.67.222.222ns-755.awsdns-30.net.
TTL 172800

Text dump

; DNS report for 243.194.251.205.in-addr.arpa (205.251.194.243)
; 2026-11-09 05:55:07 UTC, 129 queries in 0.54 s, zone 194.251.205.in-addr.arpa

;; FINDINGS
;  [WARN] Nameservers disagree on the SOA serial (1 on ns-1184.awsdns-20.org, ns-1841.awsdns-38.co.uk, ns-458.awsdns-57.com, ns-620.awsdns-13.net; 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 194.251.205.in-addr.arpa itself lists ns-1184.awsdns-20.org, ns-1841.awsdns-38.co.uk, ns-458.awsdns-57.com, ns-620.awsdns-13.net. Make the two lists match.
;  [INFO] 194.251.205.in-addr.arpa isn't signed with DNSSEC, so resolvers can't tell forged answers from real ones.

;; RECORDS (authoritative, from ns-1184.awsdns-20.org (205.251.196.160))
243.194.251.205.in-addr.arpa.	172800	IN	PTR	ns-755.awsdns-30.net.

;; TRACE
;  243.194.251.205.in-addr.arpa PTR
;  . @k.root-servers.net (193.0.14.129) 38 ms [NOERROR qr]: referral to in-addr.arpa.
in-addr.arpa.		NS	f.in-addr-servers.arpa.	; 193.0.9.1 2a13:27c0:30::1
in-addr.arpa.		NS	e.in-addr-servers.arpa.	; 203.119.86.101 2001:dd8:6::101
in-addr.arpa.		NS	a.in-addr-servers.arpa.	; 199.180.182.53 2620:37:e000::53
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	b.in-addr-servers.arpa.	; 199.253.183.183 2001:500:87::87
in-addr.arpa.	86400	IN	DS	54956 8 2 E0E2BF5CFBD66572CA05EC18267D91509BA6A9405AF05C3FD4141DFA45200C08
in-addr.arpa.	86400	IN	DS	53696 8 2 13E5501C56B20394DA921B51412D48B7089C5EB6957A7C58553C4D4D424F04DF
in-addr.arpa.	86400	IN	DS	47054 8 2 5CAFCCEC201D1933B4C9F6A9C8F51E51F3B39979058AC21B8DF1B1F281CBC6F2
in-addr.arpa.	86400	IN	DS	63982 8 2 AAF4FB5D213EF25AE44679032EBE3514C487D7ABD99D7F5FEC3383D030733C73
;  in-addr.arpa. @a.in-addr-servers.arpa (199.180.182.53) 93 ms [NOERROR qr]: referral to 205.in-addr.arpa.
205.in-addr.arpa.		NS	x.arin.net.	; 199.180.180.63 2001:500:f0::63
205.in-addr.arpa.		NS	arin.authdns.ripe.net.	; 193.0.9.10 2a13:27c0:30::10
205.in-addr.arpa.		NS	z.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	r.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.	86400	IN	DS	37219 8 2 8995F93F2EFA4E23997F6A7E3455F1E9A7C20A10A346FDF5A89AA1775664EFF9
;  205.in-addr.arpa. @y.arin.net (192.82.134.30) 6.3 ms [NOERROR qr]: referral to 194.251.205.in-addr.arpa.
194.251.205.in-addr.arpa.		NS	x3.amazonaws.org.	; 156.154.150.1
194.251.205.in-addr.arpa.		NS	pdns1.ultradns.net.	; 204.74.108.1 2001:502:f3ff::1
194.251.205.in-addr.arpa.		NS	x1.amazonaws.com.	; 156.154.64.10
194.251.205.in-addr.arpa.		NS	x2.amazonaws.com.	; 156.154.65.10
194.251.205.in-addr.arpa.		NS	x4.amazonaws.org.	; 204.74.120.1
;  194.251.205.in-addr.arpa. @x1.amazonaws.com (156.154.64.10) 5.7 ms [NOERROR qr aa]: answer
243.194.251.205.in-addr.arpa.	172800	IN	PTR	ns-755.awsdns-30.net.

;; NAMESERVERS (SOA asked of each address)
;  ns-1184.awsdns-20.org [zone]
;    205.251.196.160                         ok                        1           5.4 ms
;    2600:9000:5304:a000::1                  ok                        1           8.0 ms
;  ns-1841.awsdns-38.co.uk [zone]
;    205.251.199.49                          ok                        1           11 ms
;    2600:9000:5307:3100::1                  ok                        1           14 ms
;  ns-458.awsdns-57.com [zone]
;    205.251.193.202                         ok                        1           11 ms
;    2600:9000:5301:ca00::1                  ok                        1           14 ms
;  ns-620.awsdns-13.net [zone]
;    205.251.194.108                         ok                        1           6.1 ms
;    2600:9000:5302:6c00::1                  ok                        1           8.7 ms
;  pdns1.ultradns.net [parent]
;    204.74.108.1                            ok                        4           5.8 ms
;    2001:502:f3ff::1                        ok                        4           6.1 ms
;  x1.amazonaws.com [parent]
;    156.154.64.10                           ok                        4           6.1 ms
;  x2.amazonaws.com [parent]
;    156.154.65.10                           ok                        4           6.1 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-1184.awsdns-20.org (nameserver)
;    205.251.196.160                         PTR ns-1184.awsdns-20.org (confirmed)
;    2600:9000:5304:a000::1                  PTR ns-1184.awsdns-20.org (confirmed)
;  ns-1841.awsdns-38.co.uk (nameserver)
;    205.251.199.49                          PTR ns-1841.awsdns-38.co.uk (confirmed)
;    2600:9000:5307:3100::1                  PTR ns-1841.awsdns-38.co.uk (confirmed)
;  ns-458.awsdns-57.com (nameserver)
;    205.251.193.202                         PTR ns-458.awsdns-57.com (confirmed)
;    2600:9000:5301:ca00::1                  PTR ns-458.awsdns-57.com (confirmed)
;  ns-620.awsdns-13.net (nameserver)
;    205.251.194.108                         PTR ns-620.awsdns-13.net (confirmed)
;    2600:9000:5302:6c00::1                  PTR ns-620.awsdns-13.net (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-755.awsdns-30.net (PTR target)
;    205.251.194.243                         PTR ns-755.awsdns-30.net (confirmed)
;    2600:9000:5302:f300::1                  PTR ns-755.awsdns-30.net (confirmed)

;; PUBLIC RESOLVERS
;  Cloudflare PTR   ns-755.awsdns-30.net.  ttl 172800
;  Google     PTR   ns-755.awsdns-30.net.  ttl 21600
;  Quad9      PTR   ns-755.awsdns-30.net.  ttl 43200
;  OpenDNS    PTR   ns-755.awsdns-30.net.  ttl 172800