CIDR Range

37.64.104.0/21

2.0K IPs /21 Societe Francaise Du Radiotelephone - SFR SA AS15557 France RIPE

Addresses

2,048

2.0K

IP Range

37.64.104.0

→ 37.64.111.255

Sub-ranges

within this block

PTR Density

100.0%

2.0K of 2.0K IPs have PTR

Reputation · trust score

A transparent 0–100 signal. Every entity starts at a neutral baseline of 65; threat-intel blocklists, exposure, reverse-DNS, routing and allocation each adjust it up or down. Higher is more trustworthy.

78/100

Moderate

How this score is built

Baseline (neutral) 65
Has a reverse-DNS (PTR) record +5
Isp allocation +5
Established allocation (14y) +3
Trust score 78 / 100

Experimental · trust-vectors model v1.3.0 — a transparent heuristic, not a definitive verdict. How it works →

Geolocation

First and last addresses in 37.64.104.0/21

37.64.104.0/21 runs from 37.64.104.0 to 37.64.111.255.

First 16

37.64.104.0 37.64.104.1 37.64.104.2 37.64.104.3 37.64.104.4 37.64.104.5 37.64.104.6 37.64.104.7 37.64.104.8 37.64.104.9 37.64.104.10 37.64.104.11 37.64.104.12 37.64.104.13 37.64.104.14 37.64.104.15

Last 16

37.64.111.240 37.64.111.241 37.64.111.242 37.64.111.243 37.64.111.244 37.64.111.245 37.64.111.246 37.64.111.247 37.64.111.248 37.64.111.249 37.64.111.250 37.64.111.251 37.64.111.252 37.64.111.253 37.64.111.254 37.64.111.255

BGP Routing

Live BGP anomalies →

Not announced as an exact prefix — covered by the announced supernet 37.64.0.0/13.

Announced prefix

37.64.0.0/13

Origin AS

AS15557

Announcement samples

11,880

Last seen

2026-10-31 22:00:17

Frequently Asked Questions

What is 37.64.104.0/21?

37.64.104.0/21 is a CIDR network block containing 2,048 IPv4 addresses (from 37.64.104.0 to 37.64.111.255). CIDR notation combines an IP address with a prefix length to define a range of addresses.

Who owns the 37.64.104.0/21 network?

The 37.64.104.0/21 range is allocated to Societe Francaise Du Radiotelephone - SFR SA and announced via AS15557 from France.

Last updated: 2026-10-31 23:09:06 UTC