Sh4mefulIP Address: 46.21.87.111
This page shows DMARC authentication failure data for this IP address. Learn more about this data.
Geolocation Information
- Country:
- NL The Netherlands
- Region:
- North Holland
- City:
- Amsterdam
- Coordinates:
- 52.3759, 4.8975
WHOIS Information
- Network Name:
- LT-MELBICOM-20101103
- CIDR:
46.21.87.0/24- Owner:
- ORG-MU30-RIPE
Analysis
This IP was observed generating a single DMARC authentication failure on November 13, 2024. With only one data point, the event is better read as a single suspicious observation than a sustained campaign. Every message observed from this source failed both SPF and DKIM verification. Receiving mail providers applied a reject disposition, refusing delivery outright.
The address has no reverse DNS record. Legitimate mail infrastructure almost always publishes a PTR record, because major receivers (Gmail, Microsoft 365, Yahoo) penalize or reject mail without one, and because it is a baseline operational hygiene expectation. Its absence, combined with authentication failure, is consistent with a host being used to originate spoofed mail rather than one misconfigured by a legitimate operator.
Geolocation places the host in Amsterdam, The Netherlands, on infrastructure operated by ORG-MU30-RIPE. Abuse-reporting channels in this jurisdiction are generally responsive, and reports to the network operator can result in timely remediation.
The address is registered to ORG-MU30-RIPE (LT-MELBICOM-20101103). Enterprise-registered addresses that appear in DMARC failure data are typically either compromised hosts on the organization's network or outbound mail relays that are not properly authorized in the domain's SPF record.
Across the wider LT-MELBICOM-20101103 network, 1 distinct IP has been associated with 1 authentication failures over 1 observed messages, spanning 1 country. Activity on this network is sparse in this dataset, suggesting isolated rather than systematic abuse.
If your domain appears in the From header of mail from this address, treat it as probable spoofing. Verify that your SPF record does not authorize this host, directly or through nested include mechanisms, and that no DKIM selector you publish has been issued to it. If both checks come back clean, the receiver's reject action is doing its job.
Your DMARC policy posture matters more than any IP-level response here. The enforcement action applied to this mail indicates your policy is already providing protection. Maintaining p=reject across all your domains closes the gap for attackers who manage partial alignment. Domains that remain at p=none long-term tend to be impersonated repeatedly, because the cost to the attacker of attempting is effectively zero.
Blocking this individual address has limited durability: an attacker can rotate to another address in the same /24 subnet at effectively zero cost. More durable responses include monitoring aggregate DMARC reports so new sources are visible as they emerge, tightening SPF to remove overly permissive include chains or +all mechanisms, and ensuring DKIM is signing every legitimate outbound stream so alignment failures are unambiguous. The formal abuse contact for ORG-MU30-RIPE is listed in RIPE WHOIS records, and timely remediation is achievable through that channel.
External Reputation Lookups
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