Microsoft patents firewall that checks UDP traffic before letting it in
Microsoft describes a firewall method for User Datagram Protocol (UDP) traffic that temporarily allows a small amount of data to pass through to a private network. It then monitors the behavior of that data to verify if the connection is legitimate, blocking the rest of the traffic if the check fails.
In the filing’s own words
In a UDP firewall, a flow of packets is received from a public communications network, the flow of packets being sent into a private communications network. The firewall forwards a threshold amount of the flow of packets into the private communications network and validates the flow of packets in response to receiving a packet from the private communications network. In response to the validation failing the firewall blocks the flow of packets. In response to the validation succeeding the firewall allows the flow of packets to continue to be forwarded into the private communications network.
What exactly they claim (claim 1)
1. A method performed by a firewall for mitigating denial of service attacks in a communications network, the method comprising: receiving a flow of packets from a first network directed toward a second network; forwarding, by the firewall, an initial portion of the flow of packets into the second network; monitoring one or more observable behaviors associated with the forwarded portion of the flow; determining, based on the one or more observable behaviors, whether the flow is valid; and in response to determining that the flow is not valid, blocking subsequent packets of the flow, and in response to determining that the flow is valid, permitting subsequent packets of the flow to pass through the firewall.
Facts
- Company
- Microsoft (MICROSOFT TECHNOLOGY LICENSING, LLC)
- Official title
- USER DATAGRAM PROTOCOL FIREWALL
- Publication number
- US20260312936A1
- Application number
- 19710337
- Filed
- Jun 16, 2026
- Published
- Oct 8, 2026
- Inventors
- 1
- Claims
- 20
Classified under
H04L 63/0236 Electricity & electronicsH04L 63/0272 Electricity & electronicsH04L 65/65 Electricity & electronicsMore from Microsoft in Security & privacy
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Summaries are simplified from the filing’s own abstract and first claim. A patent filing is not a product announcement.
Patent data and drawings: U.S. Patent and Trademark Office (USPTO). Nebula is not affiliated with or endorsed by the USPTO.