codeforces.com - dns.ninja

`codeforces.com`

DNSSEC	⚠️ Not signed
A	2606:4700:20::681a:6a4^{🇺🇸 Cloudflare2606:4700:20::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	2606:4700:20::681a:7a4^{🇺🇸 Cloudflare2606:4700:20::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	2606:4700:20::ac43:44fe^{🇺🇸 Cloudflare2606:4700:20::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	104.26.6.164^{Cloudflare104.26.0.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	104.26.7.164^{Cloudflare104.26.0.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	172.67.68.254^{🇺🇸 Cloudflare172.67.64.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
NS	`fred.ns.cloudflare.com` ⭐
		A	2606:4700:58::adf5:3b71^{🇺🇸 Cloudflare2606:4700:50::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`fred.ns.cloudflare.com`
		A	2803:f800:50::6ca2:c171^{🇨🇷 Cloudflare2803:f800:50::/45 LACNIC generated route6 for CloudFlare Latin America S.R.L}
			PTR	`fred.ns.cloudflare.com`
		A	2a06:98c1:50::ac40:2171^{🇺🇸 Cloudflare2a06:98c1:50::/45}
			PTR	`fred.ns.cloudflare.com`
		A	108.162.193.113^{🇺🇸 Cloudflare108.162.193.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`fred.ns.cloudflare.com`
		A	172.64.33.113^{🇺🇸 Cloudflare172.64.33.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`fred.ns.cloudflare.com`
		A	173.245.59.113^{🇺🇸 Cloudflare173.245.59.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`fred.ns.cloudflare.com`
NS	`jean.ns.cloudflare.com`
		A	2606:4700:50::adf5:3a79^{🇺🇸 Cloudflare2606:4700:50::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`jean.ns.cloudflare.com`
		A	2803:f800:50::6ca2:c079^{🇨🇷 Cloudflare2803:f800:50::/45 LACNIC generated route6 for CloudFlare Latin America S.R.L}
			PTR	`jean.ns.cloudflare.com`
		A	2a06:98c1:50::ac40:2079^{🇺🇸 Cloudflare2a06:98c1:50::/45}
			PTR	`jean.ns.cloudflare.com`
		A	108.162.192.121^{🇺🇸 Cloudflare108.162.192.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`jean.ns.cloudflare.com`
		A	172.64.32.121^{🇺🇸 Cloudflare172.64.32.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`jean.ns.cloudflare.com`
		A	173.245.58.121^{🇺🇸 Cloudflare173.245.58.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`jean.ns.cloudflare.com`
MX	`mx.yandex.net` ⭐
		A	2a02:6b8::311^{🇷🇺 TELETECH2a02:6b8::/32 Yandex network}
			PTR	`mxfront.stable.qloud-b.yandex.net`
		A	77.88.21.249^{🇷🇺 TELETECH77.88.0.0/18 Yandex enterprise network}
			PTR	`mxfront.stable.qloud-b.yandex.net`
TXT	`google-site-verification=l4G0k0hCtL44oR2JYae12tG2VSyD0ig5OEN4oKGz6IY`
TXT	`loaderio=17e74635884b3872197928c7ea0123c5`
TXT	`v=spf1 ip4:77.234.204.67 ip4:95.163.252.67 include:_spf.yandex.net -all`
HTTPS	HTTP/2 ✓ hints match
		IPv4 hints	104.26.6.164, 104.26.7.164, 172.67.68.254
		IPv6 hints	2606:4700:20::681a:6a4, 2606:4700:20::681a:7a4, 2606:4700:20::ac43:44fe
SOA	`fred.ns.cloudflare.com`dns@cloudflare.com serial=2408827545

`com`

	DNSSEC	🔒 Signed (DS record present)
	NS	`a.gtld-servers.net` ⭐
	NS	`b.gtld-servers.net`
	NS	`c.gtld-servers.net`
	NS	`d.gtld-servers.net`
	NS	`e.gtld-servers.net`
	NS	`f.gtld-servers.net`
	NS	`g.gtld-servers.net`
	NS	`h.gtld-servers.net`
	NS	`i.gtld-servers.net`
	NS	`j.gtld-servers.net`
	NS	`k.gtld-servers.net`
	NS	`l.gtld-servers.net`
	NS	`m.gtld-servers.net`
	SOA	`a.gtld-servers.net`nstld@verisign-grs.com serial=1784808542

rank #17736 globally
rank #8683 in the tld
WOT: SAFE (94/100)
📈 Tranco rank: #6,269

Previously MX for

codeforces.com

Subdomains

espresso.codeforces.com

pubsub.codeforces.com

m2.codeforces.com

st.codeforces.com

www.codeforces.com

mx1.codeforces.com

m1.codeforces.com

sta.codeforces.com

assets.codeforces.com

mirror.codeforces.com

polygon.codeforces.com

Same first word

codeforces.netlify.app

codeforces.com

codeforces.net

codeforces.org

codeforces.ru

codeforces.me

codeforces.live

Similar names

codesforce.com

frescocode.com

codeforecs.s3-us-west-2.amazonaws.com

DNS History

17 records (9 active, 8 former)

○NSdns1.yandex.net2015-08-29 → 2021-11-05 · 4 obs

● 2015-08-29 20:42:02
● 2021-11-05 04:25:10
○ 2026-02-16 00:32:00
○ 2026-07-23 12:37:50

○NSdns2.yandex.net2015-08-29 → 2021-11-05 · 4 obs

● 2015-08-29 20:42:02
● 2021-11-05 04:25:10
○ 2026-02-16 00:32:00
○ 2026-07-23 12:37:50

●NSfred.ns.cloudflare.com2026-02-16 → 2026-07-23 · 3 obs

○ 2021-11-05 04:25:10
● 2026-02-16 00:32:00
● 2026-07-23 12:37:50

●NSjean.ns.cloudflare.com2026-02-16 → 2026-07-23 · 3 obs

○ 2021-11-05 04:25:10
● 2026-02-16 00:32:00
● 2026-07-23 12:37:50

○MXcodeforces.com2019-05-30 → 2019-05-30 · 4 obs

○ 2017-02-12 03:47:42
● 2019-05-30 18:59:28
○ 2020-01-25 08:53:08
○ 2026-07-23 12:37:50

●MXmx.yandex.net2015-08-29 → 2026-07-23 · 5 obs

● 2015-08-29 20:42:02
● 2017-02-12 03:47:42
○ 2019-05-30 18:59:28
● 2020-01-25 08:53:08
● 2026-07-23 12:37:50

●A104.26.6.1642026-02-16 → 2026-07-23 · 3 obs

○ 2021-11-05 04:25:10
● 2026-02-16 00:32:00
● 2026-07-23 12:37:50

●A104.26.7.1642026-02-16 → 2026-07-23 · 3 obs

○ 2021-11-05 04:25:10
● 2026-02-16 00:32:00
● 2026-07-23 12:37:50

●A172.67.68.2542026-02-16 → 2026-07-23 · 3 obs

○ 2021-11-05 04:25:10
● 2026-02-16 00:32:00
● 2026-07-23 12:37:50

○A188.93.56.352016-09-07 → 2016-09-07 · 4 obs

○ 2016-08-26 10:08:20
● 2016-09-07 22:31:58
○ 2016-11-28 23:01:44
○ 2026-07-23 12:37:50

○A212.193.33.272015-08-29 → 2017-02-12 · 7 obs

● 2015-08-29 20:42:02
● 2016-08-26 10:08:20
○ 2016-09-07 22:31:58
● 2016-11-28 23:01:44
● 2017-02-12 03:47:42
○ 2019-05-30 18:59:28
○ 2026-07-23 12:37:50

○A213.248.110.1262021-03-18 → 2021-11-05 · 5 obs

○ 2020-01-25 08:53:08
● 2021-03-18 11:40:26
● 2021-11-05 04:25:10
○ 2026-02-16 00:32:00
○ 2026-07-23 12:37:50

●A2606:4700:20::681a:6a42026-02-16 → 2026-07-23 · 3 obs

○ 2021-11-05 04:25:10
● 2026-02-16 00:32:00
● 2026-07-23 12:37:50

●A2606:4700:20::681a:7a42026-02-16 → 2026-07-23 · 3 obs

○ 2021-11-05 04:25:10
● 2026-02-16 00:32:00
● 2026-07-23 12:37:50

●A2606:4700:20::ac43:44fe2026-02-16 → 2026-07-23 · 3 obs

○ 2021-11-05 04:25:10
● 2026-02-16 00:32:00
● 2026-07-23 12:37:50

○A77.234.215.1952019-05-30 → 2019-05-30 · 4 obs

○ 2017-02-12 03:47:42
● 2019-05-30 18:59:28
○ 2020-01-25 08:53:08
○ 2026-07-23 12:37:50

○A81.27.240.1262020-01-25 → 2020-01-25 · 4 obs

○ 2019-05-30 18:59:28
● 2020-01-25 08:53:08
○ 2021-03-18 11:40:26
○ 2026-07-23 12:37:50

🔍 DNS Trace

📋 Delegation Chain

Zone	Nameservers	Glue
com	k.gtld-servers.net, h.gtld-servers.net, a.gtld-servers.net, b.gtld-servers.net...	-
codeforces.com	fred.ns.cloudflare.com, jean.ns.cloudflare.com	12 records

✅ Authoritative Response

Server:108.162.192.121

NS records: fred.ns.cloudflare.com, jean.ns.cloudflare.com

🔒 DNSSEC Status

⚠️ Insecure (no DNSSEC)

No DS record for codeforces.com (unsigned zone)

⏱️ Timing

Total: 392ms | Queries: -

📄 Records

Type	Count	Sample Data
A	3	`104.26.6.164, 172.67.68.254...`
AAAA	3	`2606:4700:20::681a:7a4, 2606:4700:20::ac43:44fe...`
NS	2	`fred.ns.cloudflare.com, jean.ns.cloudflare.com`
MX	1	`mx.yandex.net (pri: 10)`
TXT	3	`google-site-verification=l4G0k0hCtL44oR2, loaderio=17e74635884b3872197928c7ea0123c...`
HTTPS	1	`{"priority":1,"target":".","alpn":["h2"]`
SOA	1	`fred.ns.cloudflare.com dns.cloudflare.co`

📌 Glue Records Collected

Total: 12

Out-of-bailiwick: 12 (fred.ns.cloudflare.com, fred.ns.cloudflare.com, fred.ns.cloudflare.com...)

Analysis

Hierarchy

codeforces.com is a parent domain; its children include espresso.codeforces.com, pubsub.codeforces.com, m2.codeforces.com, st.codeforces.com, www.codeforces.com and a few other host names.

IP Addresses

With 6 IP addresses in total, codeforces.com resolves to 104.26.6.164, 104.26.7.164, 172.67.68.254 and 3 other.

Among the host names that share IP numbers with codeforces.com are motocrosscenter.com, crypto-news-6320.xlog.app, www.helleniqenergy.gr and two others.

Name Servers

DNS delegation for codeforces.com points to two name servers: fred.ns.cloudflare.com and jean.ns.cloudflare.com.

codeforces.com has the same name server delegation as a number of other domains, such as ostel.me, factoftheday.net, ishostedby.com and two more.

codeforces.com partially shares its NS delegation with several other domains, including sweetpay.com, renalresearch.com, qjae.org and two others.

These name servers often co-occur with the name servers fatima.ns.cloudflare.com.

Host names resolving to 6 IP numbers:

fred.ns.cloudflare.com has IP addresses 108.162.193.113, 172.64.33.113 and 173.245.59.113, plus 3 other.

jean.ns.cloudflare.com has IP addresses 108.162.192.121, 172.64.32.121 and 173.245.58.121, plus 3 other.

Mail Servers

codeforces.com routes its mail through a single mail server, mx.yandex.net.

codeforces.com has the same mail server arrangement as a number of other domains, for example trebl.ru, gambrinus.ru, 9050.ru and two more.

codeforces.com shares at least some of its mail servers with other domains — for example legat.by, allminsk.biz, belarbet.ru and two more.

It is common to find these mail servers paired with the mail servers mx.yandex.ru.

The host mx.yandex.net resolves to 77.88.21.249 and 2a02:6b8::311 — two IP addresses.