DMARC Spoof Detection, Czechia
ClearClear FilterThis page shows DMARC authentication failures originating from Czechia. Learn more about this data.
Czechia accounts for 9 DMARC authentication failures observed by sh4meful over the observation window, sourced from 8 distinct IP addresses across 7 networks. This represents approximately 0.1% of total failure volume observed. Activity from Czechia has declined over the last 30 days compared with the prior 30-day period. The most active source is GRAPESC with 2 failures across 2 IP addresses.
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Top Networks in Czechia
Ten most active networks sourcing DMARC failures from Czechia:
| Network | Organization | Failures | Distinct IPs | Top City |
|---|---|---|---|---|
| GRAPESC | — | 2 | 2 | Chomutov |
| SFERIA-CZ | — | 1 | 1 | Jablonec nad Nisou |
| TR-VFNET-20120625 | — | 1 | 1 | Baška |
| Vodafone-BROADBAND-XXXIII | — | 1 | 1 | Prague |
| Vodafone-BROADBAND-DV-V | — | 2 | 1 | Brno |
| OPAVANET | — | 1 | 1 | Opava |
| RIPE-ERX-192-124-170-0 | — | 1 | 1 | — |
GRAPESC and SFERIA-CZ together account for 46% of failure volume from this country. Distribution across many networks is consistent with commodity spoofing infrastructure operating from this geography.
Failure Activity Over Time
Peak activity was observed in the week of July 27, 2026 with 8 failures recorded. Activity in the most recent 30-day window declined sharply compared with the prior period (0 vs 15 failures).
Regional Context
Compared with peer geographies in Eastern Europe, Czechia's failure volume is comparable to the regional median. Countries in this region collectively contributed 3% of failures observed.
Failures
Showing 1-9 of 9 failures, affecting 24 messages| Date ▼ | Source IP | Country | City | Network | Messages |
|---|---|---|---|---|---|
| 8/6/2026 | CZ Czechia | Žatec | 3 | ||
| 8/4/2026 | CZ Czechia | Jablonec nad Nisou | 4 | ||
| 8/2/2026 | CZ Czechia | Baška | 4 | ||
| 8/2/2026 | CZ Czechia | Chomutov | 4 | ||
| 7/9/2026 | CZ Czechia | Brno | 1 | ||
| 7/8/2026 | CZ Czechia | Brno | 1 | ||
| 6/8/2026 | CZ Czechia | Opava | 2 | ||
| 12/11/2025 | CZ Czechia | Prague | 4 | ||
| 10/19/2024 | CZ Czechia | 1 |
What This Means
Country-level patterns don't imply that mail from Czechia 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.