`atcoder.jp`

DNSSEC	⚠️ Not signed
A	18.161.21.43^{🇺🇸 Amazon18.161.16.0/21}
		PTR	`server-18-161-21-43.bos50.r.cloudfront.net`
A	18.161.21.71^{🇺🇸 Amazon18.161.16.0/21}
A	18.161.21.77^{🇺🇸 Amazon18.161.16.0/21}
A	18.161.21.116^{🇺🇸 Amazon18.161.16.0/21}
NS	`ns-96.awsdns-12.com` ⭐
		A	2600:9000:5300:6000::1^{🇺🇸 Amazon2600:9000:5300::/48 - CloudFront}
			PTR	`ns-96.awsdns-12.com`
		A	205.251.192.96^{🇺🇸 Amazon205.251.192.0/24 prefix}
			PTR	`ns-96.awsdns-12.com`
NS	`ns-1144.awsdns-15.org`
		A	2600:9000:5304:7800::1^{🇺🇸 Amazon2600:9000:5304::/48 - CloudFront}
			PTR	`ns-1144.awsdns-15.org`
		A	205.251.196.120^{🇺🇸 Amazon205.251.196.0/24 prefix}
			PTR	`ns-1144.awsdns-15.org`
NS	`ns-1543.awsdns-00.co.uk`
		A	2600:9000:5306:700::1^{🇺🇸 Amazon2600:9000:5306::/48 - CloudFront}
			PTR	`ns-1543.awsdns-00.co.uk`
		A	205.251.198.7^{🇺🇸 Amazon205.251.198.0/24 prefix}
			PTR	`ns-1543.awsdns-00.co.uk`
NS	`ns-890.awsdns-47.net`
		A	2600:9000:5303:7a00::1^{🇺🇸 Amazon2600:9000:5303::/48 - CloudFront}
			PTR	`ns-890.awsdns-47.net`
		A	205.251.195.122^{🇺🇸 Amazon205.251.195.0/24 prefix}
			PTR	`ns-890.awsdns-47.net`
MX	`aspmx.l.google.com` ⭐
		A	2607:f8b0:4004:c1b::1b^{🇺🇸 Google2607:f8b0:4004::/48}
			PTR	`wv-in-f27.1e100.net`
		A	142.251.111.27^{🇺🇸 Google142.251.111.0/24}
			PTR	`bk-in-f27.1e100.net`
MX	`alt1.aspmx.l.google.com`⁽²⁰⁾
		A	2607:f8b0:4023:2801::1a^{🇺🇸 Google2607:f8b0::/32}
			PTR	`lcausi-in-f26.1e100.net`
		A	192.178.128.26^{🇺🇸 Google192.178.128.0/24}
			PTR	`lcausi-in-f26.1e100.net`
MX	`alt2.aspmx.l.google.com`⁽²⁰⁾
		A	2607:f8b0:4023:3003::1a^{🇺🇸 Google2607:f8b0::/32}
			PTR	`yulnkjt-in-f26.1e100.net`
		A	172.253.145.26^{🇺🇸 Google172.253.145.0/24}
			PTR	`yulnkjt-in-f26.1e100.net`
MX	`aspmx2.googlemail.com`⁽³⁰⁾
		A	2800:3f0:4003:c0f::1a^{🇨🇱 Google2800:3f0:4003::/48}
		A	108.177.123.27^{🇺🇸 Google108.177.123.0/24}
			PTR	`lcscld-in-f27.1e100.net`
MX	`aspmx3.googlemail.com`⁽³⁰⁾
		A	2607:f8b0:4023:3003::1a^{🇺🇸 Google2607:f8b0::/32}
			PTR	`yulnkjt-in-f26.1e100.net`
		A	172.253.145.26^{🇺🇸 Google172.253.145.0/24}
			PTR	`yulnkjt-in-f26.1e100.net`
MX	`aspmx4.googlemail.com`⁽³⁰⁾
		A	2a00:1450:4009:c0f::1b^{🇬🇧 Google2a00:1450:4009::/48}
			PTR	`yulhrs-in-f27.1e100.net`
		A	192.178.223.27^{🇺🇸 Google192.178.223.0/24}
			PTR	`yulhrs-in-f27.1e100.net`
MX	`aspmx5.googlemail.com`⁽³⁰⁾
		A	2a00:1450:400c:c00::1b^{🇧🇪 Google2a00:1450:400c::/48}
			PTR	`ws-in-f27.1e100.net`
			PTR	`ws-in-x1b.1e100.net`
		A	173.194.76.27^{🇺🇸 Google173.194.76.0/24}
			PTR	`ws-in-f27.1e100.net`
TXT	`1password-site-verification=H3CJM364F5GI5P3VXH2PYFGCKI`
TXT	`MS=ms90685883`
TXT	`google-site-verification=IIyyB5yMWakA7SnvZLuqk-eBDlEj647aY0Rq-c80uIg`
TXT	`google-site-verification=iiXXCv8YJjdE0FWPz6zq0ispBt688ytJaOQfOpwuU3A`
TXT	`pardot884953=58ccd91e72a6f94be7450fef89ee32f712f9e18afb5273954e7d09781c220ec1`
TXT	`stripe-verification=e726551d53f6bea6b1a960e876e9fd88c34f32b723a3b2ecb1a91dfc3...`
TXT	`v=spf1 a:atcoder.jp include:_spf.google.com include:aspmx.pardot.com include:...`
SOA	`ns-96.awsdns-12.com`awsdns-hostmaster@amazon.com serial=1

`jp`

	DNSSEC	🔒 Signed (DS record present)
	NS	`z.dns.jp` ⭐
	NS	`a.dns.jp`
	NS	`b.dns.jp`
	NS	`c.dns.jp`
	NS	`d.dns.jp`
	NS	`e.dns.jp`
	NS	`f.dns.jp`
	NS	`g.dns.jp`
	NS	`h.dns.jp`
	SOA	`z.dns.jp`root@dns.jp serial=1778352303

rank #54758 globally
rank #1039 in the tld
📈 Tranco rank: #37,103

Subdomains

img.atcoder.jp

past.atcoder.jp

Same first word

atcoder.co.jp

atcoder.org

atcoder.jp

atcoder.biz

atcoder.info

Similar names

teradoc.fr

artdeco.store

dotcaer.com

redcoat.ai

decoart.at

codeart.co.uk

dotcrea.net

roadtec.com.uy

artdeco.se

codetra.com

codeart.pl

rodatec.com

artedoc.nl

artdeco.hk

artcode.in

artcode.com.au

artdeco.ch

daocert.com

artdeco.info

artdeco.cz

artdeco.de

artdeco.ca

artedco.com

cartedo.com

tradeco.com.ar

codeart.us

decoart.es

octaedr.info

docrate.com

tradeco.online

tradeco.pro

artcode.ltd

redcoat.de

decoart.fi

cadoret.com

coredat.at

cordate.tw

artcode.co.uk

artcode.by

cortade.net

codeart.co.il

caterdo.com

credota.live

redcoat.biz

tradeco.ca

coredat.net

doreact.com

cotrade.cn

artcode.co.jp

cotarde.com

redcoat.eu

artdeco.at

cardeto.it

artdeco.org.au

artcode.com

tradeco.cz

roadtec.com

doratec.ch

decoart.co.uk

roadtec.com.ua

teradoc.com

cotrade.co

redacto.org

ardotec.com

coredat.com

doctera.com

decorat.ru

codeart.vn

tedraco.com

ecotrad.org

decarto.com

deactro.nl

decorat.com

doecart.com

decoart.fr

decoart.to

tradeco.com.vn

tarcode.ru

decoart.online

cadoret.fr

treadco.com

codeart.com.au

decotra.com

cadoret.myshopify.com

artcode.com.ua

tadecor.vn

roadtec.net

cotrade.de

cardeto.org

artdeco.nl

artecod.net

dertaco.net

artcode.eu

cotrade.it

ecotrad.it

artdeco.diamonds

cadoret.ca

decoart.ru

decorat.bg

DNS History

61 records (15 active, 46 former)

●NSns-1144.awsdns-15.org2017-05-24 → 2026-05-09 · 3 obs

○ 2016-07-16 04:50:00
● 2017-05-24 06:16:14
● 2026-05-09 19:27:46

●NSns-1543.awsdns-00.co.uk2017-05-24 → 2026-05-09 · 3 obs

○ 2016-07-16 04:50:00
● 2017-05-24 06:16:14
● 2026-05-09 19:27:46

●NSns-890.awsdns-47.net2017-05-24 → 2026-05-09 · 3 obs

○ 2016-07-16 04:50:00
● 2017-05-24 06:16:14
● 2026-05-09 19:27:46

●NSns-96.awsdns-12.com2017-05-24 → 2026-05-09 · 3 obs

○ 2016-07-16 04:50:00
● 2017-05-24 06:16:14
● 2026-05-09 19:27:46

○NSns1.value-domain.com2015-08-13 → 2016-07-16 · 4 obs

● 2015-08-13 18:44:32
● 2016-07-16 04:50:00
○ 2017-05-24 06:16:14
○ 2026-05-09 19:27:46

○NSns2.value-domain.com2015-08-13 → 2016-07-16 · 4 obs

● 2015-08-13 18:44:32
● 2016-07-16 04:50:00
○ 2017-05-24 06:16:14
○ 2026-05-09 19:27:46

●MXalt1.aspmx.l.google.com2015-08-13 → 2026-05-09 · 2 obs

● 2015-08-13 18:44:32
● 2026-05-09 19:27:46

●MXalt2.aspmx.l.google.com2015-08-13 → 2026-05-09 · 2 obs

● 2015-08-13 18:44:32
● 2026-05-09 19:27:46

●MXaspmx.l.google.com2015-08-13 → 2026-05-09 · 2 obs

● 2015-08-13 18:44:32
● 2026-05-09 19:27:46

●MXaspmx2.googlemail.com2015-08-13 → 2026-05-09 · 2 obs

● 2015-08-13 18:44:32
● 2026-05-09 19:27:46

●MXaspmx3.googlemail.com2015-08-13 → 2026-05-09 · 2 obs

● 2015-08-13 18:44:32
● 2026-05-09 19:27:46

●MXaspmx4.googlemail.com2015-08-13 → 2026-05-09 · 2 obs

● 2015-08-13 18:44:32
● 2026-05-09 19:27:46

●MXaspmx5.googlemail.com2015-08-13 → 2026-05-09 · 2 obs

● 2015-08-13 18:44:32
● 2026-05-09 19:27:46

○A108.156.85.1092026-03-31 → 2026-05-08 · 44 obs

○ 2026-03-29 22:43:20
● 2026-03-31 10:52:36
○ 2026-04-02 06:31:10
○ 2026-04-09 07:48:54
● 2026-04-10 09:03:20
○ 2026-04-10 13:38:10
● 2026-04-10 14:45:46
○ 2026-04-10 23:38:46
○ 2026-04-12 06:38:00
● 2026-04-12 11:36:40
○ 2026-04-13 01:37:50
● 2026-04-13 07:09:50
○ 2026-04-13 08:05:26
○ 2026-04-14 07:02:46
● 2026-04-14 07:51:18
● 2026-04-15 13:20:46
○ 2026-04-15 18:24:28
● 2026-04-17 01:42:46
○ 2026-04-17 15:43:44
○ 2026-04-24 21:22:18
● 2026-04-25 01:03:40
○ 2026-04-25 02:21:32
○ 2026-04-25 08:02:42
● 2026-04-25 11:53:46
○ 2026-04-25 17:53:16
○ 2026-04-27 13:39:04
● 2026-04-27 17:44:52
○ 2026-04-27 18:40:04
○ 2026-04-29 03:58:12
● 2026-04-29 11:44:44
○ 2026-04-29 12:55:46
○ 2026-04-30 14:32:52
● 2026-04-30 15:18:08
○ 2026-04-30 17:08:32
● 2026-04-30 19:36:52
○ 2026-04-30 21:49:12
○ 2026-05-06 05:45:06
● 2026-05-06 11:00:46
● 2026-05-06 14:45:50
○ 2026-05-06 15:42:02
○ 2026-05-07 23:35:20
● 2026-05-08 02:23:56
○ 2026-05-08 04:30:06
○ 2026-05-09 19:27:46

○A108.156.85.1112026-03-31 → 2026-05-08 · 44 obs

○A108.156.85.462026-03-31 → 2026-05-08 · 44 obs

○A108.156.85.892026-03-31 → 2026-05-08 · 44 obs

○A13.113.48.1902018-06-16 → 2018-09-08 · 5 obs

○ 2017-05-24 06:16:14
● 2018-06-16 00:59:16
● 2018-09-08 01:26:56
○ 2026-02-14 20:08:58
○ 2026-05-09 19:27:46

○A13.226.209.1132026-02-14 → 2026-04-13 · 30 obs

○ 2018-09-08 01:26:56
● 2026-02-14 20:08:58
● 2026-02-19 04:49:56
○ 2026-02-19 07:44:18
○ 2026-02-19 12:36:58
● 2026-02-19 13:08:28
● 2026-02-24 02:07:36
○ 2026-02-24 08:58:44
● 2026-02-25 04:31:32
● 2026-03-01 05:17:48
○ 2026-03-01 07:17:12
○ 2026-03-01 14:41:46
● 2026-03-03 00:36:20
● 2026-03-04 01:19:50
○ 2026-03-04 04:08:04
○ 2026-03-12 05:55:12
● 2026-03-12 06:42:52
○ 2026-03-12 10:09:52
○ 2026-03-18 05:21:00
● 2026-03-18 11:17:50
○ 2026-03-18 13:29:54
○ 2026-03-20 08:14:06
● 2026-03-20 10:44:06
○ 2026-03-20 11:16:46
● 2026-03-21 15:01:56
○ 2026-03-21 21:29:32
○ 2026-04-13 07:09:50
● 2026-04-13 08:05:26
○ 2026-04-14 07:02:46
○ 2026-05-09 19:27:46

○A13.226.209.192026-02-14 → 2026-04-13 · 30 obs

○A13.226.209.242026-02-14 → 2026-04-13 · 30 obs

○A13.226.209.572026-02-14 → 2026-04-13 · 30 obs

○A13.33.235.1142026-03-25 → 2026-03-25 · 4 obs

○ 2026-03-24 13:03:54
● 2026-03-25 11:25:00
○ 2026-03-25 13:48:44
○ 2026-05-09 19:27:46

○A13.33.235.1272026-03-25 → 2026-03-25 · 4 obs

○ 2026-03-24 13:03:54
● 2026-03-25 11:25:00
○ 2026-03-25 13:48:44
○ 2026-05-09 19:27:46

○A13.33.235.352026-03-25 → 2026-03-25 · 4 obs

○ 2026-03-24 13:03:54
● 2026-03-25 11:25:00
○ 2026-03-25 13:48:44
○ 2026-05-09 19:27:46

○A13.33.235.682026-03-25 → 2026-03-25 · 4 obs

○ 2026-03-24 13:03:54
● 2026-03-25 11:25:00
○ 2026-03-25 13:48:44
○ 2026-05-09 19:27:46

●A18.161.21.1162026-04-24 → 2026-05-09 · 21 obs

○ 2026-04-23 17:23:40
● 2026-04-24 12:34:40
○ 2026-04-24 17:23:42
○ 2026-04-26 11:53:48
● 2026-04-26 15:25:46
○ 2026-04-26 16:55:58
● 2026-04-26 18:02:06
○ 2026-04-26 22:49:40
○ 2026-04-27 03:57:48
● 2026-04-27 08:58:26
● 2026-04-27 13:39:04
○ 2026-04-27 17:44:52
○ 2026-04-30 22:57:22
● 2026-04-30 23:35:48
○ 2026-05-01 00:12:00
○ 2026-05-03 06:06:30
● 2026-05-03 09:12:14
○ 2026-05-03 11:11:10
○ 2026-05-09 06:18:44
● 2026-05-09 19:27:42
● 2026-05-09 19:27:46

●A18.161.21.432026-04-24 → 2026-05-09 · 21 obs

●A18.161.21.712026-04-24 → 2026-05-09 · 21 obs

●A18.161.21.772026-04-24 → 2026-05-09 · 21 obs

○A18.165.9.1172026-04-06 → 2026-04-06 · 4 obs

○ 2026-04-05 20:25:44
● 2026-04-06 08:50:04
○ 2026-04-06 10:45:08
○ 2026-05-09 19:27:46

○A18.165.9.352026-04-06 → 2026-04-06 · 4 obs

○ 2026-04-05 20:25:44
● 2026-04-06 08:50:04
○ 2026-04-06 10:45:08
○ 2026-05-09 19:27:46

○A18.165.9.82026-04-06 → 2026-04-06 · 4 obs

○ 2026-04-05 20:25:44
● 2026-04-06 08:50:04
○ 2026-04-06 10:45:08
○ 2026-05-09 19:27:46

○A18.165.9.872026-04-06 → 2026-04-06 · 4 obs

○ 2026-04-05 20:25:44
● 2026-04-06 08:50:04
○ 2026-04-06 10:45:08
○ 2026-05-09 19:27:46

○A18.244.202.402026-04-03 → 2026-05-06 · 27 obs

○ 2026-04-02 06:31:10
● 2026-04-03 04:54:28
○ 2026-04-03 17:40:14
○ 2026-04-03 18:30:02
● 2026-04-04 02:17:08
○ 2026-04-04 06:29:14
○ 2026-04-04 07:03:24
● 2026-04-05 00:55:36
○ 2026-04-05 07:17:12
○ 2026-04-07 02:21:42
● 2026-04-08 03:24:30
○ 2026-04-08 15:43:32
● 2026-04-09 04:20:28
○ 2026-04-09 07:48:54
○ 2026-04-11 03:56:16
● 2026-04-11 11:19:48
○ 2026-04-12 06:38:00
○ 2026-04-18 11:51:02
● 2026-04-18 22:59:02
○ 2026-04-19 19:41:18
○ 2026-05-03 14:26:28
● 2026-05-03 15:49:34
○ 2026-05-04 01:24:46
○ 2026-05-06 14:45:50
● 2026-05-06 15:42:02
○ 2026-05-06 16:21:14
○ 2026-05-09 19:27:46

○A18.244.202.512026-04-03 → 2026-05-06 · 27 obs

○A18.244.202.752026-04-03 → 2026-05-06 · 27 obs

○A18.244.202.792026-04-03 → 2026-05-06 · 27 obs

○A3.162.112.162026-04-19 → 2026-04-19 · 4 obs

○ 2026-04-18 22:59:02
● 2026-04-19 19:41:18
○ 2026-04-22 00:48:16
○ 2026-05-09 19:27:46

○A3.162.112.262026-04-19 → 2026-04-19 · 4 obs

○ 2026-04-18 22:59:02
● 2026-04-19 19:41:18
○ 2026-04-22 00:48:16
○ 2026-05-09 19:27:46

○A3.162.112.682026-04-19 → 2026-04-19 · 4 obs

○ 2026-04-18 22:59:02
● 2026-04-19 19:41:18
○ 2026-04-22 00:48:16
○ 2026-05-09 19:27:46

○A3.162.112.742026-04-19 → 2026-04-19 · 4 obs

○ 2026-04-18 22:59:02
● 2026-04-19 19:41:18
○ 2026-04-22 00:48:16
○ 2026-05-09 19:27:46

○A3.169.231.1122026-02-24 → 2026-03-28 · 40 obs

○ 2026-02-24 02:07:36
● 2026-02-24 08:58:44
○ 2026-02-25 04:31:32
○ 2026-03-01 05:17:48
● 2026-03-01 07:17:12
● 2026-03-01 14:41:46
○ 2026-03-03 00:36:20
○ 2026-03-04 01:19:50
● 2026-03-04 04:08:04
○ 2026-03-04 07:49:36
● 2026-03-06 18:07:04
○ 2026-03-08 00:13:48
○ 2026-03-08 10:16:58
● 2026-03-08 14:15:14
○ 2026-03-08 15:54:16
○ 2026-03-08 17:23:56
● 2026-03-08 18:22:38
○ 2026-03-08 22:14:50
● 2026-03-09 06:48:08
○ 2026-03-12 05:55:12
○ 2026-03-13 07:09:24
● 2026-03-14 00:31:36
● 2026-03-14 02:48:22
○ 2026-03-14 10:28:20
● 2026-03-14 11:40:54
○ 2026-03-15 17:41:22
○ 2026-03-15 18:48:58
● 2026-03-16 03:11:34
○ 2026-03-17 12:33:22
● 2026-03-18 05:21:00
○ 2026-03-18 11:17:50
○ 2026-03-18 13:29:54
● 2026-03-20 08:14:06
○ 2026-03-20 10:44:06
● 2026-03-20 11:16:46
○ 2026-03-21 15:01:56
○ 2026-03-25 13:48:44
● 2026-03-28 09:37:26
○ 2026-03-28 14:14:42
○ 2026-05-09 19:27:46

○A3.169.231.452026-02-24 → 2026-03-28 · 40 obs

○A3.169.231.482026-02-24 → 2026-03-28 · 40 obs

○A3.169.231.552026-02-24 → 2026-03-28 · 40 obs

○A52.69.167.992017-05-24 → 2017-05-24 · 4 obs

○ 2016-07-16 04:50:00
● 2017-05-24 06:16:14
○ 2018-06-16 00:59:16
○ 2026-05-09 19:27:46

○A52.85.31.282026-03-08 → 2026-04-05 · 16 obs

○ 2026-03-06 18:07:04
● 2026-03-08 00:13:48
○ 2026-03-08 10:16:58
○ 2026-03-08 15:54:16
● 2026-03-08 17:23:56
○ 2026-03-08 18:22:38
○ 2026-03-29 08:40:30
● 2026-03-29 22:43:20
○ 2026-03-31 10:52:36
● 2026-04-02 06:31:10
○ 2026-04-03 04:54:28
○ 2026-04-05 00:55:36
● 2026-04-05 07:17:12
● 2026-04-05 20:25:44
○ 2026-04-06 08:50:04
○ 2026-05-09 19:27:46

○A52.85.31.412026-03-08 → 2026-04-05 · 16 obs

○A52.85.31.492026-03-08 → 2026-04-05 · 16 obs

○A52.85.31.582026-03-08 → 2026-04-05 · 16 obs

○A54.230.201.1182026-04-23 → 2026-05-09 · 47 obs

○ 2026-04-22 15:43:14
● 2026-04-23 11:39:44
● 2026-04-23 17:23:40
○ 2026-04-24 12:34:40
● 2026-04-24 17:23:42
● 2026-04-24 21:22:18
○ 2026-04-25 01:03:40
● 2026-04-25 02:21:32
● 2026-04-25 08:02:42
○ 2026-04-25 11:53:46
● 2026-04-25 17:53:16
● 2026-04-26 11:53:48
○ 2026-04-26 15:25:46
● 2026-04-26 16:55:58
○ 2026-04-26 18:02:06
● 2026-04-26 22:49:40
● 2026-04-27 03:57:48
○ 2026-04-27 08:58:26
○ 2026-04-27 17:44:52
● 2026-04-27 18:40:04
● 2026-04-29 03:58:12
○ 2026-04-29 11:44:44
● 2026-04-29 12:55:46
● 2026-04-30 14:32:52
○ 2026-04-30 15:18:08
● 2026-04-30 17:08:32
○ 2026-04-30 19:36:52
● 2026-04-30 21:49:12
● 2026-04-30 22:57:22
○ 2026-04-30 23:35:48
● 2026-05-01 00:12:00
● 2026-05-03 06:06:30
○ 2026-05-03 09:12:14
● 2026-05-03 11:11:10
● 2026-05-03 14:26:28
○ 2026-05-03 15:49:34
● 2026-05-04 01:24:46
● 2026-05-06 05:45:06
○ 2026-05-06 11:00:46
○ 2026-05-06 15:42:02
● 2026-05-06 16:21:14
● 2026-05-07 23:35:20
○ 2026-05-08 02:23:56
● 2026-05-08 04:30:06
● 2026-05-09 06:18:44
○ 2026-05-09 19:27:42
○ 2026-05-09 19:27:46

○A54.230.201.272026-04-23 → 2026-05-09 · 47 obs

○A54.230.201.32026-04-23 → 2026-05-09 · 47 obs

○A54.230.201.642026-04-23 → 2026-05-09 · 47 obs

○A54.64.33.2152018-06-16 → 2018-09-08 · 5 obs

○ 2017-05-24 06:16:14
● 2018-06-16 00:59:16
● 2018-09-08 01:26:56
○ 2026-02-14 20:08:58
○ 2026-05-09 19:27:46

○A54.64.36.2352015-08-13 → 2016-07-16 · 4 obs

● 2015-08-13 18:44:32
● 2016-07-16 04:50:00
○ 2017-05-24 06:16:14
○ 2026-05-09 19:27:46

○A99.86.91.302026-02-19 → 2026-04-22 · 78 obs

○ 2026-02-19 04:49:56
● 2026-02-19 07:44:18
● 2026-02-19 12:36:58
○ 2026-02-19 13:08:28
○ 2026-03-04 04:08:04
● 2026-03-04 07:49:36
○ 2026-03-06 18:07:04
○ 2026-03-08 00:13:48
● 2026-03-08 10:16:58
○ 2026-03-08 14:15:14
● 2026-03-08 15:54:16
○ 2026-03-08 17:23:56
○ 2026-03-08 18:22:38
● 2026-03-08 22:14:50
○ 2026-03-09 06:48:08
● 2026-03-12 05:55:12
○ 2026-03-12 06:42:52
● 2026-03-12 10:09:52
● 2026-03-13 07:09:24
○ 2026-03-14 00:31:36
○ 2026-03-14 02:48:22
● 2026-03-14 10:28:20
○ 2026-03-14 11:40:54
● 2026-03-15 17:41:22
● 2026-03-15 18:48:58
○ 2026-03-16 03:11:34
● 2026-03-17 12:33:22
○ 2026-03-18 05:21:00
○ 2026-03-18 11:17:50
● 2026-03-18 13:29:54
○ 2026-03-20 08:14:06
○ 2026-03-21 15:01:56
● 2026-03-21 21:29:32
● 2026-03-24 13:03:54
○ 2026-03-25 11:25:00
● 2026-03-25 13:48:44
○ 2026-03-28 09:37:26
● 2026-03-28 14:14:42
● 2026-03-29 08:40:30
○ 2026-03-29 22:43:20
○ 2026-04-03 04:54:28
● 2026-04-03 17:40:14
● 2026-04-03 18:30:02
○ 2026-04-04 02:17:08
● 2026-04-04 06:29:14
● 2026-04-04 07:03:24
○ 2026-04-05 00:55:36
○ 2026-04-06 08:50:04
● 2026-04-06 10:45:08
● 2026-04-07 02:21:42
○ 2026-04-08 03:24:30
● 2026-04-08 15:43:32
○ 2026-04-09 04:20:28
● 2026-04-09 07:48:54
○ 2026-04-10 09:03:20
● 2026-04-10 13:38:10
○ 2026-04-10 14:45:46
● 2026-04-10 23:38:46
● 2026-04-11 03:56:16
○ 2026-04-11 11:19:48
● 2026-04-12 06:38:00
○ 2026-04-12 11:36:40
● 2026-04-13 01:37:50
○ 2026-04-13 07:09:50
○ 2026-04-13 08:05:26
● 2026-04-14 07:02:46
○ 2026-04-14 07:51:18
○ 2026-04-15 13:20:46
● 2026-04-15 18:24:28
○ 2026-04-17 01:42:46
● 2026-04-17 15:43:44
● 2026-04-18 11:51:02
○ 2026-04-18 22:59:02
○ 2026-04-19 19:41:18
● 2026-04-22 00:48:16
● 2026-04-22 15:43:14
○ 2026-04-23 11:39:44
○ 2026-05-09 19:27:46

○A99.86.91.512026-02-19 → 2026-04-22 · 78 obs

○A99.86.91.92026-02-19 → 2026-04-22 · 78 obs

○A99.86.91.982026-02-19 → 2026-04-22 · 78 obs

🔍 DNS Trace

📋 Delegation Chain

Zone	Nameservers	Glue
jp	d.dns.jp, b.dns.jp, h.dns.jp, e.dns.jp...	-
atcoder.jp	ns-1543.awsdns-00.co.uk, ns-96.awsdns-12.com, ns-890.awsdns-47.net, ns-1144.awsdns-15.org	-

✅ Authoritative Response

Server:205.251.192.96

NS records: ns-1543.awsdns-00.co.uk, ns-96.awsdns-12.com, ns-890.awsdns-47.net, ns-1144.awsdns-15.org

🔒 DNSSEC Status

⚠️ Insecure (no DNSSEC)

No DS record for atcoder.jp (unsigned zone)

⏱️ Timing

Total: 827ms | Queries: -

📄 Records

Type	Count	Sample Data
A	4	`18.161.21.43, 18.161.21.116...`
NS	4	`ns-1144.awsdns-15.org, ns-1543.awsdns-00.co.uk...`
MX	7	`aspmx.l.google.com (pri: 10), alt1.aspmx.l.google.com (pri: 20)...`
TXT	7	`1password-site-verification=H3CJM364F5GI, MS=ms90685883...`
SOA	1	`ns-96.awsdns-12.com awsdns-hostmaster.am`

Analysis

Hierarchy

atcoder.jp is a parent of img.atcoder.jp and past.atcoder.jp.

IP Addresses

atcoder.jp resolves to four IPs: 18.161.21.43, 18.161.21.71, 18.161.21.77 and 18.161.21.116.

Name Servers

atcoder.jp is delegated to four name servers: ns-96.awsdns-12.com, ns-890.awsdns-47.net, ns-1144.awsdns-15.org and ns-1543.awsdns-00.co.uk.

At least part of the name servers for atcoder.jp are shared with other domains, for instance 2013expo.or.kr, biblebee.com, equinoxfitness.com, rwapitest.com and inkl.com.