Sh4mefulIP Address: 149.8.13.133
Dormant. IP address 149.8.13.133 is registered to Leidos, Inc and geolocates to United States. It first appeared in sh4meful's dataset on September 17, 2025 and was most recently observed on October 1, 2025. Over the observation window, it has failed DMARC alignment 4 times across 2 distinct sender domains. It has no reverse DNS record. Network context: this address sits within LEIDOS-149-8-0-0-16 (Leidos, Inc), a network sh4meful has observed producing 13 failures across 4 distinct IPs during the same window.
Failure Activity Over Time
This IP has claimed to send from 2 sender domains monitored by sh4meful. The narrow domain set is consistent with a targeted spoofing pattern.
This page shows DMARC authentication failure data for this IP address. Learn more about this data.
Geolocation Information
- Country:
- US United States
- Coordinates:
- 37.751, -97.822
WHOIS Information
- Network Name:
- LEIDOS-149-8-0-0-16
- CIDR:
149.8.0.0/16- Owner:
- Leidos, Inc.
- Org ID:
LEIDO- Address:
- 1750 Presidents Street, Reston, VA 20190
Analysis
This IP has generated DMARC authentication failures across 13 messages between September 17, 2025 and October 1, 2025. Every message observed from this source failed both SPF and DKIM verification. Receiving mail providers applied a quarantine disposition, routing messages to spam or junk folders.
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 United States, on infrastructure operated by Leidos, Inc. 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 Leidos, Inc (LEIDOS-149-8-0-0-16). 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 LEIDOS-149-8-0-0-16 network, 4 distinct IPs have been associated with 13 authentication failures over 29 observed messages, spanning 1 country. The failure pattern suggests a mix of abuse sources on this network.
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 quarantine 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 Leidos, Inc is listed in ARIN WHOIS records, and timely remediation is achievable through that channel.
Network Topology
This address is part of LEIDOS-149-8-0-0-16 (Leidos, Inc), announced from United States. 4 IPs in this network have been observed in sh4meful's dataset.
External Reputation Lookups
Look up this IP in external threat intelligence and reputation databases (opens in new tab):
Nearby IPs
The following IP addresses share the same /24 subnet as 149.8.13.133 and have appeared in sh4meful's dataset. Related activity in nearby addresses often indicates infrastructure operated by a single actor or provider.
- 149.8.13.136 — 6 failures, first seen 10 months ago, the same day as this address.
- 149.8.13.135 — 1 failure, first seen 10 months ago, 9 days after this address.
Recommended Action
If this IP appears in your own DMARC reports, treat it as an unauthorized sender unless you have specifically verified it as a legitimate service you use. Ensure your DMARC policy is at p=quarantine or p=reject to prevent delivery of messages this IP claims to send from your domain. If you're new to DMARC, our complete guide walks through the mechanics.