Sh4meful DMARC Spoof Detection
IP Address: 104.47.56.171
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.
About this Data
▶The data here is from DMARC analysis for domains I administer, drawn from a larger dataset (comprising millions of authentication records and messages). These entries are from email attempts that failed both SPF and DKIM (and there are often alignment issues - hidden here). In many cases, these failures indicate unauthorized use of the domain name, and are commonly associated with spoofing, phishing, or other abusive mail activity.
Geolocation Information
- Country:
- US United States
- Region:
- Washington
- Coordinates:
- 47.6109, -122.3303
WHOIS Information
- Network Name:
- MSFT
- CIDR:
104.40.0.0/13- Reverse DNS:
-
mail-co1nam11lp2171.outbound.protection.outlook.com
Last updated: 2/5/2026
Failures Detected from this IP
Showing 1-28 of 28 (failures, affecting 49 messages)| Date ▼ | Messages |
|---|---|
| 9/19/2025 | 1 |
| 9/10/2025 | 2 |
| 9/9/2025 | 1 |
| 7/18/2025 | 1 |
| 7/9/2025 | 2 |
| 7/1/2025 | 1 |
| 6/27/2025 | 3 |
| 5/15/2025 | 1 |
| 5/2/2025 | 3 |
| 2/26/2025 | 6 |
| 2/14/2025 | 5 |
| 1/17/2025 | 1 |
| 12/21/2024 | 1 |
| 12/20/2024 | 1 |
| 12/19/2024 | 1 |
| 12/18/2024 | 1 |
| 12/5/2024 | 1 |
| 12/4/2024 | 2 |
| 11/20/2024 | 2 |
| 11/13/2024 | 1 |
| 11/12/2024 | 1 |
| 11/8/2024 | 1 |
| 10/30/2024 | 1 |
| 10/23/2024 | 3 |
| 10/16/2024 | 1 |
| 9/27/2024 | 2 |
| 9/20/2024 | 1 |
| 9/13/2024 | 2 |