Sh4meful DMARC Spoof Detection
IP Address: 159.183.224.100
Twilio SendGrid is a cloud-based Email Service Provider (ESP), or Mail Transfer Agent (MTA). It operates as a high-volume, cloud-based SMTP service to send, receive, and relay both transactional and marketing emails. These signals could be indicative of a failure during legitimate sends (through Sendgrid), or could be signal of a spam/spoof attempt using their service which is common enough we're not treating this as a confounder.
About this Data
▶The data here is from DMARC analysis for domains I administer, drawn from a larger dataset (comprising millions of authentication records and messages). These entries are from email attempts that failed both SPF and DKIM (and there are often alignment issues - hidden here). In many cases, these failures indicate unauthorized use of the domain name, and are commonly associated with spoofing, phishing, or other abusive mail activity.
Geolocation Information
- Country:
- US United States
- Coordinates:
- 37.751, -97.822
WHOIS Information
- Network Name:
- TWILI-11
- CIDR:
159.183.0.0/16- Reverse DNS:
-
s.wfbtzhsq.outbound-mail.sendgrid.net
Last updated: 2/5/2026