# 37.66.5.21 — IP Intelligence Summary

37.66.5.21 is an IPv4 address, with approximate network location Gretz-Armainvilliers, France. Its reverse DNS name is 21.5.66.37.rev.sfr.net. As of November 6, 2026, IPDebrief rates it Low Risk (0/100); no anonymizing service was detected.

- Canonical page: https://ipdebrief.com/37.66.5.21
- Last updated: 2026-11-06

## Ownership

- Organization: —
- Network name: —
- Allocated block: —
- ASN: —
- Regional registry: —
- Registered holder: —
- Routing operator: —
- Network registration country: —
- Registrant address country: —

## Location

- City: Gretz-Armainvilliers
- Region: Île-de-France
- Country: France
- Time zone: Europe/Paris

Approximate network location; registration and certificate addresses are not server-location evidence.

## Network classification

- Infrastructure type: —
- Datacenter / hosting: no
- Residential: no
- Mobile: no
- Anycast: Unverified (not proof of unicast)
- Tor exit node: no
- VPN: no
- Proxy: no

## Risk assessment

- Assessment: Low Risk (0/100)
- Blocklist listings: 0
- Suspicious activity indicators: no
- Spam source: no

## Reverse DNS

- 21.5.66.37.rev.sfr.net
- Forward-confirmed: yes

## DNS posture

Mail authentication and CAA are optional domain policies, not IP-wide requirements.

- spf: Not checked
- dmarc: Not checked
- fcrDns: Not checked
- dnssec: Not checked
- caa: Not checked

## Nearby addresses

- 37.66.5.106 (https://ipdebrief.com/37.66.5.106)
- 37.66.5.112 (https://ipdebrief.com/37.66.5.112)
- 37.66.5.227 (https://ipdebrief.com/37.66.5.227)

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Source: IPDebrief, "37.66.5.21 IP intelligence", https://ipdebrief.com/37.66.5.21, updated 2026-11-06. Assessments are probabilistic.