codeforces.com
Observed 2026-07-17T19:29:17.829Z (4h 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
172.67.68.254104.26.7.164104.26.6.1642606:4700:20::681a:7a4+2 more
Cloudflareserves the site
NS
fred.ns.cloudflare.comjean.ns.cloudflare.com
cloudflare.comanswers its DNS
MX
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 time333 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
172.67.68.254104.26.7.164104.26.6.164
AAAA 3
2606:4700:20::681a:7a42606:4700:20::ac43:44fe2606:4700:20::681a:6a4
MX 1
10mx.yandex.net
TXT 4
loaderio=17e74635884b3872197928c7ea0123c5google-site-verification=l4G0k0hCtL44oR2JYae12tG2VSyD0ig5OEN4oKGz6IYv=spf1 ip4:77.234.204.67 ip4:95.163.252.67 include:_spf.yandex.net -allv=DMARC1; p=reject
NS 2
fred.ns.cloudflare.comjean.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 receiptEd25519 Receipt
- Receipt ID
af799a6c-6cc2-491a-a8a8-9dca04e99324- Output Hash
d03a46b40e951163bdeb049fd49df5f0cd7b7803d29db9e58d5237806a8165da- Signature
ed25519:16bae5a9206c1e507db8c18dbbf25ccfa73a37e24ffdbc239ce1fac717ad0917a07505d1c54400a52ad70840c38a962edb1cdb7728e844e9757738fdb895550e- Public Key
ed25519:7aad40f2d6399c207fe2fc15aade04a78324787a355d36725cc90687f9e10cff- Parent
(genesis)- Plane
- fast