Rank #1,051Updated November 10, 2026
cwi.nl
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cwi.nl is registered with SURF B.V. since May 1, 1986 (40.5 years). The site runs on Django, cdnjs, Python and 2 other technologies. Its email security grade is C. Its SSL certificate is issued by Hellenic Academic and Research Institutions CA and is valid for 89 more days.
- Domain age
- 40.5 yrs
- Technologies
- 5
- Email security
- C
- SSL days left
- 89
Registration
| Registrar | SURF B.V. |
|---|---|
| IANA ID | 0000 |
| Registered | May 1, 1986 |
| Updated | January 16, 2026 |
| Status | active |
| Name servers | dwalin.nikhef.nl, ns1.cwi.nl, ns1.zurich.surf.net, ns2.cwi.nl |
| DNSSEC | Signed |
DNS records
| Type | Value | TTL |
|---|---|---|
| A | 192.16.191.48 | 86400 |
| MX | mx.soverin.net 10 | 300 |
| NS | ns1.cwi.nl | 86400 |
| NS | ns1.zurich.surf.net | 86400 |
| NS | ns2.cwi.nl | 86400 |
| NS | dwalin.nikhef.nl | 86400 |
| TXT | MS=ms63043750 | 86400 |
| TXT | HARICA-SnDN4Irx82qOUXNni8S | 86400 |
| TXT | Centrum Wiskunde & Informatica | 86400 |
| TXT | ZOOM_verify_-TwabqfPQI2RrsWzDjTwfQ | 86400 |
| TXT | ZOOM_verify_QtFtKLPNUTBlqUfH6kXTNZ | 86400 |
| TXT | apple-domain-verification=vKvt2VfbB2WZUhzQ | 86400 |
| TXT | Science Park 123, 1098 XG Amsterdam, Netherlands | 86400 |
| TXT | CWI (Centrum Wiskunde & Informatica)=pnqgTeOiurzbz4yD | 86400 |
| TXT | adobe-idp-site-verification=a8667c98581a66df82f18dd9b4ec9ad04d2b0214fda298afa04b69ae89b16b4d | 86400 |
| TXT | v=spf1 ip4:192.16.191.0/27 ip4:192.174.88.179 ip4:192.174.88.180 ip4:13.58.74.171 include:_spf.surfmailfilter.nl include:projects5.greenlightsolutions.nl include:spf.protection.outlook.com ~all | 86400 |
Technology stack
SSL certificate
| Valid | Valid |
|---|---|
| Issuer | GR, GEANT TLS ECC 1, Hellenic Academic and Research Institutions CA |
| Expires | February 7, 2027 |
| Days remaining | 89 |
| Protocol | TLSv1.3 |
| Names | cwi.nl, www.cwi.nl |
Email security
CScore 66/100 across SPF, DMARC, DKIM, MTA-STS and BIMI.
- badSPF includes _spf.surfmailfilter.nl, which has no SPF record. That causes a permanent error.
- warnDMARC has no rua= address, so you receive no reports about mail sent as your domain.
- warnNo MTA-STS: mail sent to you can be downgraded to an unencrypted connection.
- warnNo TLS-RPT record, so you won't hear about failed encrypted deliveries.
- warnNo BIMI record (optional: shows your logo next to your emails in supporting inboxes).
- goodSPF record found.
- goodSPF ends with ~all: servers you have not listed are marked as suspicious (soft fail).
- goodDMARC policy is quarantine: failing mail goes to spam. Move to p=reject for full protection.
- goodDKIM keys found (selector: selector1, default).
- good1 MX record(s) found.
Homepage metadata
| Title | Home |
|---|---|
| Language | en |
| Indexable | Yes |
| Word count | 881 |
About cwi.nl
Who is the registrar of cwi.nl?
cwi.nl is registered with SURF B.V. (IANA ID 0000).
What technology does cwi.nl use?
We detected 5 technologies on cwi.nl, including cdnjs, Python, HSTS, Django, Nginx.
Does cwi.nl protect its email with SPF and DMARC?
cwi.nl scores 66/100 (grade C) for email security. SPF includes _spf.surfmailfilter.nl, which has no SPF record. That causes a permanent error. DMARC has no rua= address, so you receive no reports about mail sent as your domain.
What are the name servers of cwi.nl?
cwi.nl uses ns1.cwi.nl, ns1.zurich.surf.net, ns2.cwi.nl, dwalin.nikhef.nl.