Overview
Fly.io operates a CDN or reverse-proxy network associated with AS40509.
This record includes the representative IPv4 CIDR 137.66.40.0/24. It is not an exhaustive list of the network’s address space or current routing announcements.
This is a network-origin record, not an exact physical-facility location or proof that a request is automated. Evaluate the ASN and CIDR together with the User-Agent, request path, request rate, session behavior, and application context before enforcement.
Provider and network
- Provider Name
- Fly.io
- Organization
- Fly.io, Inc.
- ISP
- Fly.io, Inc.
- ASN
-
AS40509 - ASN Name
- FLY
- Network Name
- Fly.io network
- Services
- CDN, edge delivery, reverse proxy, security, caching, application acceleration
- Provider Type
- CDN and edge
- Network Type
- CDN/reverse proxy
IP range
- IP Version
- IPv4
- IP / CIDR
-
137.66.40.0/24 - Range Scope
- Representative
- Range Label
- Representative CIDR
- Range Start
-
137.66.40.0 - Range End
-
137.66.40.255 - Example IP
-
137.66.40.1 - Example IP Decimal
-
2302814209
Network scope
- Registry Country
- US
Traffic and handling
- Traffic Classification
- CDN / Proxy Traffic
- Traffic Label
- CDN / Proxy
- Risk Level
- Low
- Recommended Action
- Log by default. Do not block the provider range wholesale. Restore and validate the trusted client IP before applying visitor-level rules.
- Default Rule Action
- Log
- Common Pattern
- Shared edge addresses can represent many unrelated visitors, proxied applications, cached requests, and security-filtered traffic.
- Detection Notes
- Match AS40509 and representative CIDR 137.66.40.0/24. Validate the proxy configuration and apply visitor-level rules to the restored client IP rather than the shared edge address.