codeforces.com

Observed 2026-07-15T09:03:07.440Z (14h ago). Every field below was attested with an Ed25519 signature at scan time.

Up right now

Runs onCloudflare

Registered withGandi SAS

Also usesGoogle Search Console

IPv6 · 8 subdomains · education

Every line above is a signed observation. Check the math at the bottom of the page.

INFRASTRUCTURE MAPwhat codeforces.com actually stands on - every host below is a signed observation

codeforces.com

A / AAAA

104.26.7.164172.67.68.254104.26.6.1642606:4700:20::681a:7a4+2 more

Cloudflareserves the site

jean.ns.cloudflare.comfred.ns.cloudflare.com

cloudflare.comanswers its DNS

mx.yandex.net

yandex.netreceives its email

HTTPS probe

ok Responding normally (2xx) 200 OK

HTTP status200

Servercloudflare

TLS protocolHTTP/2

TLS issuernot observed

Behind Cloudflareyes

Response time244 ms

DNS resolutionNOERROR

Every field above is part of the same signed observation as the records below. Blank means not observed, never "none".

DNS Records

A 3

104.26.7.164
172.67.68.254
104.26.6.164

AAAA 3

2606:4700:20::681a:7a4
2606:4700:20::ac43:44fe
2606:4700:20::681a:6a4

MX 1

10mx.yandex.net

TXT 4

v=spf1 ip4:77.234.204.67 ip4:95.163.252.67 include:_spf.yandex.net -all
google-site-verification=l4G0k0hCtL44oR2JYae12tG2VSyD0ig5OEN4oKGz6IY
loaderio=17e74635884b3872197928c7ea0123c5
v=DMARC1; p=reject

NS 2

jean.ns.cloudflare.com
fred.ns.cloudflare.com

SOA 1

fred.ns.cloudflare.com dns.cloudflare.com

TLS Certificates (0)

None.

Subdomains (8)

The proof

Signed at scan time. Check the math yourself. Every line above is part of one signed observation. Re-hash it and check the Ed25519 signature in your own browser; nothing leaves your machine.

Verify this receipt

Put the receipt on your own site. A live badge showing what DomainDrift observes and signs for codeforces.com. It updates itself. It attests a signed observation - not that the site is safe.

<a href="https://domaindrift.io/t/codeforces.com">
  <img src="https://domaindrift.io/badge/codeforces.com.svg"
       width="300" height="64" alt="DomainDrift signed observations for codeforces.com">
</a>

Ed25519 Receipt

Receipt ID: a181c219-8e2e-408c-b707-20c831bb81e2
Output Hash: 3c447ca3aff792526195d7b56461c892ab9418196dd6d9da1e84b9b5c80c9ca5
Signature: ed25519:285e7373660f89d461d1fd06c8797b21fdb54cff7c1803b2fca60aa4d5946dc1d5bc751b521614fa01d4e9b3830860c113a99533ab658076d4b0fc4be4b4bf0f
Public Key: ed25519:d610d74ef18f683e5beb859d241d5e67dff0c122e8928b06bec1c2476f4ba27b
Parent: (genesis)
Plane: fast

Verify this in your browser

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