Sh4mefulIP Address: 129.162.252.140
This page shows DMARC authentication failure data for this IP address. Learn more about this data.
Geolocation Information
- Country:
- US United States
- Region:
- Texas
- City:
- San Antonio
- Coordinates:
- 29.3991, -98.6421
WHOIS Information
- Network Name:
- SWRI-NET
- CIDR:
129.162.0.0/16- Owner:
- Southwest Research Institute
- Org ID:
SRI-5- Address:
- 6220 Culebra Road, Dept. 32 P.O. Drawer 28510, San Antonio, TX 78228-0510
- Reverse DNS:
-
esg260-1.itc.swri.edu
Last updated: 2/5/2026
Analysis
This IP was observed generating a single DMARC authentication failure on July 9, 2025. 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 quarantine disposition, routing messages to spam or junk folders.
The reverse DNS record resolves to esg260-1.itc.swri.edu. Whether this represents legitimate mail infrastructure depends on whether the hostname aligns with the domains this address is claiming to send on behalf of.
Geolocation places the host in San Antonio, United States, on infrastructure operated by Southwest Research Institute. 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 Southwest Research Institute (SWRI-NET). 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 SWRI-NET network, 2 distinct IPs have been associated with 7 authentication failures over 13 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 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 Southwest Research Institute is listed in ARIN WHOIS records, and timely remediation is achievable through that channel.
External Reputation Lookups
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