Open CDN detection tool

codeforces.com CDN Detection: Possible Cloudflare Usage

CNAME, HTTP header, and ASN signals indicate that codeforces.com may be using Cloudflare, with 45% confidence. Review the evidence and latest check time.

Checked At: 10/2/2026, 22:42:09

Likely using Cloudflare

This result is based on public DNS, HTTP, and network signals and may update with later observations.

codeforces.comHTTP Status 200 10/2/2026, 22:42:09

Overall Confidence

45%Evidence strength

Based on the independent evidence matched in this detection

Node Distribution

Current snapshot
Cloudflare 45%

Detection Path

Complete · 5 stages

DNS Resolution
-

Complete · 6 addresses

CNAME Chain
-

Complete · 1 CNAME found

IP / ASN
-

Complete · 6 IPs, 4 ASNs

HTTP Response
-

Complete · response headers collected

Fingerprint Score
-

Complete · 4 evidence types

Evidence Timeline

Observed facts ordered by collection time

Checked At: 10/2/2026, 22:42:09
02:42:09 PM
HTTP
header: cf-ray
Cloudflare

Strong

02:42:15 PM
HTTP
header: cf-ray
Cloudflare

Strong

02:42:16 PM
HTTP
header: cf-ray
Cloudflare

Strong

02:42:16 PM
HTTP
header: cf-ray
Cloudflare

Strong

02:42:16 PM
HTTP
header: cf-ray
Cloudflare

Strong

Show 2 more evidence items
02:42:18 PM
HTTP
header: cf-ray
Cloudflare

Strong

02:42:18 PM
HTTP
header: cf-ray
Cloudflare

Strong

Score Explanation

Evidence strength breakdown

HTTP headers
100 / 100

Response header name and value matches

This score presents evidence strength, not statistical probability. A shared ASN or cloud network cannot confirm a CDN on its own.

Node and Routing Differences

Resolution results and access signals observed by region and carrier

Collected just now
RegionCarrierResolved IPCDN ProviderASNLocationTTLConfidenceTTFB
Northern China中国电信104.26.6.164/32Cloudflare-中国 北京市-
45%
3201ms
Central node-172.67.68.254/32Cloudflare--69s
45%
-
Western North AmericaOverseas104.26.6.164/32Cloudflare-美国 圣何塞-
45%
393ms
Eastern North AmericaOverseas2606:4700:20::681a:6a4/128Cloudflare-美国 波士顿-
45%
458ms
East AsiaOverseas104.26.7.164/32Cloudflare-中国香港特别行政区 香港-
45%
390ms
Southwestern China中国电信2606:4700:20::681a:6a4/128Cloudflare-中国 昆明市-
45%
1934ms
Southern ChinaBGP多线104.26.7.164/32Cloudflare-中国 广州市-
45%
1453ms
Node results vary by region, carrier and time7 nodes
Detection results are inferred from public DNS and HTTP signals. Confidence reflects the strength of the matched evidence and does not imply 100% certainty.
CloudflarePrimary candidate

Confidence 45%

header: cf-ray
header: cf-ray
header: cf-ray
header: cf-ray
header: cf-ray
header: cf-ray
header: cf-ray
View Cloudflare Performance Review

Methodology and limitations

Identification results are based on cross-referencing public DNS, HTTP response headers, and ASN signals; confidence indicates the strength of evidence and does not represent statistical accuracy.