IP Address: 40.107.236.100 ⚠ IP Confounder

⚠ IP Confounder Detected: Microsoft 365 Exchange Online Protection (EOP)
Outbound; PTR: *.outbound.protection.outlook.com

ℹ️ Network Annotation: Microsoft Network (365 vs Azure)

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.

Last updated: 1/29/2026

This page shows DMARC authentication failure data for this IP address. Learn more about this data.

Geolocation Information

Country:: US United States
Region:: Virginia
City:: Boydton
Coordinates:: 36.6694, -78.3877

WHOIS Information

Network Name:: MSFT
CIDR:: 40.80.0.0/12, 40.125.0.0/17, 40.124.0.0/16, 40.112.0.0/13, 40.76.0.0/14, 40.74.0.0/15, 40.120.0.0/14, 40.96.0.0/12
Owner:: Microsoft Corporation
Org ID:: MSFT
Address:: One Microsoft Way, Redmond, WA 98052
Reverse DNS:: mail-bn8nam11on2100.outbound.protection.outlook.com
Last updated: 2/5/2026

Analysis

This IP was first observed on March 13, 2024 and most recently on November 6, 2024. It has been associated with 2 failed authentication events affecting 11 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 (40.107.236.*) also appear in this dataset.

Network Topology

Failures Detected from this IP

Showing 1-2 of 2 failures, affecting 11 messages

Date ▼	Messages
11/6/2024	2
3/13/2024	9

External Reputation Lookups

Look up this IP in external threat intelligence and reputation databases (opens in new tab):

AbuseIPDB Cisco Talos Project Honey Pot GreyNoise VirusTotal Shodan Censys Spamhaus

Nearby IPs

Other IPs in the 40.107.236.0/24 range observed failing DMARC:

40.107.236.71 (5 failures), 40.107.236.98 (4 failures), 40.107.236.124 (4 failures), 40.107.236.133 (4 failures), 40.107.236.127 (4 failures), 40.107.236.108 (4 failures), 40.107.236.107 (3 failures), 40.107.236.103 (3 failures)