Sh4mefulIP Address: 23.103.199.144 ⚠ IP Confounder
GCC/Commercial outbound; PTR: *.outbound.protection.office365.us
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
- Coordinates:
- 37.751, -97.822
WHOIS Information
- Network Name:
- MSFT
- CIDR:
23.96.0.0/13- Owner:
- Microsoft Corporation
- Org ID:
MSFT- Address:
- One Microsoft Way, Redmond, WA 98052
- Reverse DNS:
-
mail-bn3usg02lp0144.outbound.protection.office365.us
Last updated: 2/5/2026
Analysis
This IP was first observed on June 4, 2025 and most recently on December 5, 2025. It has been associated with 2 failed authentication events affecting 2 messages, representing low but recurring activity. The IP belongs to MSFT (Microsoft Corporation), a network with activity associated with United States. 8 other IPs in the same /24 subnet (23.103.199.*) 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 23.103.199.0/24 range observed failing DMARC:
23.103.199.180 (3 failures), 23.103.199.177 (3 failures), 23.103.199.143 (2 failures), 23.103.199.145 (2 failures), 23.103.199.176 (2 failures), 23.103.199.178 (2 failures), 23.103.199.179 (2 failures), 23.103.199.149 (1 failure)