# 18.239.183.121 — IP Intelligence Summary

18.239.183.121 is an IPv4 address operated by Amazon.com, Inc. (AS16509), geolocated to Boston, United States. Its reverse DNS name is server-18-239-183-121.bos50.r.cloudfront.net. As of October 31, 2026, IPDebrief rates it Low Risk (25/100); no anonymizing service was detected.

- Canonical page: https://ipdebrief.com/18.239.183.121
- Last updated: 2026-10-31

## Ownership

- Organization: Amazon.com, Inc.
- Network name: AMAZON-CF
- Allocated block: 18.238.0.0/15
- ASN: AS16509 (https://ipdebrief.com/asn/16509)
- Regional registry: ARIN
- Cloud / hosting provider: Amazon Web Services

## Location

- City: Boston
- Region: US-MA
- Country: United States
- Time zone: —

## Network classification

- Infrastructure type: Unknown
- Datacenter / hosting: no
- Residential: no
- Mobile: no
- Anycast: no
- Tor exit node: no
- VPN: no
- Proxy: no

## Risk assessment

- Assessment: Low Risk (25/100)
- Blocklist listings: 0
- Suspicious activity indicators: no
- Spam source: no

## Reverse DNS

- server-18-239-183-121.bos50.r.cloudfront.net
- Forward-confirmed: yes

## Exposed services

- 80/tcp — http
- 443/tcp — https

## Analyst narrative

Analysis of IP address 18.239.183.121 identified the host as an Amazon CloudFront web server node operating under AS16509. Ownership records attributed the infrastructure to Amazon.com, Inc. within the 18.238.0.0/15 CIDR block. The address maintained a low-risk reputation score of 25 with zero blacklisting and no active threat indicators.

Geolocation data reported the node in Boston, US, yet physical RTT measurements indicated a distance of 7,625 km, violating minimum propagation constraints. The immediate subnet showed mixed usage with 33 active threat siblings, though this specific address recorded no specific malicious activity. DNS hygiene remained excellent with valid SPF and DMARC configurations. Consequently, the recommendation was to monitor the address for changes, with the severity classified as low pending resolution of the signal contradictions.

## Nearby addresses

- 18.239.183.2 (https://ipdebrief.com/18.239.183.2)
- 18.239.183.3 (https://ipdebrief.com/18.239.183.3)
- 18.239.183.4 (https://ipdebrief.com/18.239.183.4)
- 18.239.183.5 (https://ipdebrief.com/18.239.183.5)
- 18.239.183.6 (https://ipdebrief.com/18.239.183.6)
- 18.239.183.8 (https://ipdebrief.com/18.239.183.8)
- 18.239.183.9 (https://ipdebrief.com/18.239.183.9)
- 18.239.183.10 (https://ipdebrief.com/18.239.183.10)
- 18.239.183.11 (https://ipdebrief.com/18.239.183.11)
- 18.239.183.12 (https://ipdebrief.com/18.239.183.12)
- 18.239.183.13 (https://ipdebrief.com/18.239.183.13)
- 18.239.183.14 (https://ipdebrief.com/18.239.183.14)

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Source: IPDebrief, "18.239.183.121 IP intelligence", https://ipdebrief.com/18.239.183.121, updated 2026-10-31. Assessments are probabilistic.