problemchallenge.com

problemchallenge.com serves a website of its own over HTTPS. It answers on both IPv4 and IPv6, with a valid TLS certificate and MX records for mail.

40,134,347 other domains share an IP address with it.

The most recent crawl returned the page title “ProblemChallenge.com — Problem Facts, Stats & Daily Challenge” and 36,808 bytes of HTML.

Domain properties

Property	Value	Explanation
Top-level domain	.com	Statistics for all domains we know under this TLD.
Has website	yes	A website is hosted under the domain, which does not redirect to an external domain.
Has MX-record	yes	The domain has an MX record.
External redirect	no	The domain redirects to another domain.
Redirect to https	yes	The domain redirects to https.
Redirect to www.	no	The domain redirects to www.domain.
Only with www.	no	The domain can only be reached with the subdomain "www".
Only DNS, no website	no	There are no A or AAAA records in DNS.
IP-Address	Both	Shows whether the domain only has IPv4 or IPv6 or both.
SSL-Certificate	valid	Shows whether the domain has a valid SSL certificate.
Redirects	0	Number of domains that redirect to this domain.
Reverse IP	40,134,347	Number of domains with the same IP(s).

This data through the API

The data on this page is also available as JSON: /lookup for the key facts, /reverseip, /redirect and /similar for the lists, and /dnshistory with Basic and Premium. A free account comes with an API key and 100 calls a day.

curl -X POST https://api.webxtrend.com/v1.0/lookup \
  -H 'Content-Type: application/json' \
  -d '{"token": "YOUR_TOKEN", "query": "problemchallenge.com"}'

Create a free account Read the API docs

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Websites whose start page offers something similar, found by comparing the text of their start pages, across languages. Near-identical copies, parking pages and error pages are left out. The full list of up to 100 comes through the API: similar websites.

Last SSL certificate

Issuer	Google Trust Services
Valid from	10/8/2026
Valid to	1/6/2027
Time until expiry	82 days

Last successful crawl

Title	ProblemChallenge.com — Problem Facts, Stats & Daily Challenge
Description	Daily facts and stats about problem solving and famous problems, plus real challenges to put them to work. Free daily facts & stats round, streaks, badges and a live leaderboard on ProblemChallenge.com.
Content-Length	36,808 bytes

Title and description as published by the page itself in its own <title> and <meta name="description"> tags.

DNS history

IPv4 address	Last updated
104.21.90.184	4/8/2026
172.67.203.210	4/8/2026
76.76.21.21	12/11/2023

IPv6 address	Last updated
2606:4700:3031:0:0:0:6815:5ab8	6/21/2026
2606:4700:3033:0:0:0:ac43:cbd2	6/21/2026
2606:4700:3031:0:0:0:ac43:cbd2	6/5/2026
2606:4700:3035:0:0:0:6815:5ab8	6/5/2026
2a06:98c1:3120:0:0:0:0:0	5/27/2026

Mail server	Priority	Last updated
route2.mx.cloudflare.net	23	4/21/2026
route1.mx.cloudflare.net	37	4/21/2026
route3.mx.cloudflare.net	78	4/21/2026

Name server	Last updated
dexter.ns.cloudflare.com	12/11/2023
grannbo.ns.cloudflare.com	12/11/2023

The five most recent states of each record type. The full history comes through the API: DNS history.

Most recent redirect domains

No domains found.

Reverse IP neighbours

2a06:98c1:3120::3 9,992,237 domains · here since 10/12/2026

Domain	On this IP since
zzzzzzzzz.xyz	10/6/2026
zzzzzzzzum.icu	10/13/2026
zzzzzzys.com	9/19/2026
zzzzzyl1.cn	10/14/2026
zzzzzwwwppodjfdkodkloq.com	9/28/2026
zzzzzssss55.online	9/16/2026
zzzzzssss55.buzz	9/20/2026
zzzzzsss77.online	9/20/2026
zzzzzssj.com	9/14/2026
zzzzzn.com	9/20/2026
zzzzz7777.com	9/17/2026
zzzzz1.com	9/25/2026
and 9,992,224 more

2a06:98c1:3121::3 9,992,234 domains · here since 10/12/2026

Domain	On this IP since
zzzzzzzzz.xyz	10/6/2026
zzzzzzzzum.icu	10/13/2026
zzzzzzys.com	9/19/2026
zzzzzyl1.cn	10/14/2026
zzzzzwwwppodjfdkodkloq.com	9/28/2026
zzzzzssss55.online	9/16/2026
zzzzzssss55.buzz	9/20/2026
zzzzzsss77.online	9/20/2026
zzzzzssj.com	9/14/2026
zzzzzn.com	9/20/2026
zzzzz7777.com	9/17/2026
zzzzz1.com	9/25/2026
and 9,992,221 more

188.114.96.3 10,074,939 domains · here since 10/1/2026

Domain	On this IP since
zzzzzzzzz.xyz	10/6/2026
zzzzzzzzz.org	9/13/2026
zzzzzzzzum.icu	10/13/2026
zzzzzzys.com	9/19/2026
zzzzzyl1.cn	10/14/2026
zzzzzwwwppodjfdkodkloq.com	9/28/2026
zzzzzssss55.online	9/16/2026
zzzzzssss55.buzz	9/20/2026
zzzzzsss77.online	9/20/2026
zzzzzssj.com	9/14/2026
zzzzzn.com	9/20/2026
zzzzz7777.com	9/17/2026
and 10,074,926 more

188.114.97.3 10,074,937 domains · here since 10/1/2026

Domain	On this IP since
zzzzzzzzz.xyz	10/6/2026
zzzzzzzzz.org	9/13/2026
zzzzzzzzum.icu	10/13/2026
zzzzzzys.com	9/19/2026
zzzzzyl1.cn	10/14/2026
zzzzzwwwppodjfdkodkloq.com	9/28/2026
zzzzzssss55.online	9/16/2026
zzzzzssss55.buzz	9/20/2026
zzzzzsss77.online	9/20/2026
zzzzzssj.com	9/14/2026
zzzzzn.com	9/20/2026
zzzzz7777.com	9/17/2026
and 10,074,924 more

Sharing an address does not always mean sharing a server: on a CDN or a large hosting platform, millions of unrelated domains answer on the same few addresses. We measured how far that goes in Half the web sits on 276 IP addresses. The complete list of neighbours, also for an IP address, comes through the API: reverse IP lookup.

Dive into our data, search now!