Sh4mefulIP Address: 52.103.140.26 ⚠ IP Confounder
Covers 52.100-103.x.x outbound; PTR: *.outbound.protection.outlook.com
Differentiating between Office 365, including email protection services, and Azure (public cloud) when diagnosing incidents is challenging because they utilize shared Microsoft-owned IP ranges. Most of this is probably O365/Outlook or Defender protection breaking DKIM and SPF authentication. Disambiguation is a work-in-progress.
This page shows DMARC authentication failure data for this IP address. Learn more about this data.
Geolocation Information
- Country:
- US United States
- Region:
- Texas
- City:
- San Antonio
- Coordinates:
- 29.4227, -98.4927
WHOIS Information
- Network Name:
- MSFT
- CIDR:
52.112.0.0/14, 52.96.0.0/12- Owner:
- Microsoft Corporation
- Org ID:
MSFT- Address:
- One Microsoft Way, Redmond, WA 98052
- Reverse DNS:
-
mail-southcentralusazrln10223026.outbound.protection.outlook.com
Last updated: 2/5/2026
Analysis
This IP was observed on a single date: October 2, 2025. It has been associated with 1 failed authentication event affecting 1 message — a single isolated event. The IP belongs to MSFT (Microsoft Corporation), a network with activity associated with United States. 5 other IPs in the same /24 subnet (52.103.140.*) also appear in this dataset.
Network Topology
External Reputation Lookups
Look up this IP in external threat intelligence and reputation databases (opens in new tab):
Nearby IPs
Other IPs in the 52.103.140.0/24 range observed failing DMARC:
52.103.140.3 (2 failures), 52.103.140.1 (1 failure), 52.103.140.17 (1 failure), 52.103.140.25 (1 failure), 52.103.140.9 (1 failure)