Shame on you, stupid spammers.. DMARC Spoof Detection

DMARC Spoof Detection, United States

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This page shows DMARC authentication failures originating from United States. Learn more about this data.

United States accounts for 50,747 DMARC authentication failures observed by sh4meful over the observation window, sourced from 5,219 distinct IP addresses across 202 networks. This represents approximately 87.4% of total failure volume observed. Activity from United States has declined over the last 30 days compared with the prior 30-day period. The most active source is Amazon with 18,162 failures across 49 IP addresses.

Failures (Filtered)

50,747

IPs (Filtered)

5,219

Networks (Filtered)

202

Messages (Filtered)

85,172

Top Networks in United States

Ten most active networks sourcing DMARC failures from United States:

Network Organization Failures Distinct IPs Top City
AT-88-Z Amazon 18,162 49 Ashburn
UK-MICROSOFT-20060601 Microsoft 12,532 923 Des Moines
MSFT Microsoft 11,347 2,852 Des Moines
GOOGLE Google 1,083 186 โ€”
AMAZON-2011L Amazon 665 14 Ashburn
TWILI-11 Twilio 1,105 10 โ€”
SENDGRID-149-72-0-0-16 Twilio 832 5 โ€”
SENDGRID-167-89-0-0-17 Twilio 890 5 โ€”
AMAZO-4 Amazon 526 11 Ashburn
PROOFPOINT-NET-NORTH-AMERICA Proofpoint 315 83 โ€”

Amazon and Microsoft together account for 68% of failure volume from this country. Concentration in a small number of networks suggests targeted infrastructure rather than diffuse compromise.

Failure Activity Over Time

Peak activity was observed in the week of June 22, 2026 with 27 failures recorded. Activity in the most recent 30-day window declined compared with the prior period (49 vs 57 failures).

Regional Context

Compared with peer geographies in Northern America, United States's failure volume is above the regional median. Countries in this region collectively contributed 88% of failures observed.

Failures

Showing 121-130 of 50,747 failures, affecting 85,172 messages

Geographic Distribution (US)

Color intensity represents message volume

What This Means

Country-level patterns don't imply that mail from United States is inherently malicious. Many failures reflect misconfigured legitimate senders, forwarded messages that break authentication, or automated infrastructure operating without authorization. Domain owners investigating a specific failure should look at the source IP and network details rather than the country alone. Our DMARC guide explains how to interpret these signals in your own reports.