> For the complete documentation index, see [llms.txt](https://kb.nssurge.com/surge-knowledge-base/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kb.nssurge.com/surge-knowledge-base/technotes.md).

# Technotes

- [TCP Fast Open](https://kb.nssurge.com/surge-knowledge-base/technotes/tfo.md)
- [HTTP Protocol Version](https://kb.nssurge.com/surge-knowledge-base/technotes/http-protocol-version.md): This document summarizes the differences between various HTTP protocol versions, as well as the impact of Surge activation on HTTP protocol versions.
- [Local and Proxy DNS Resolution](https://kb.nssurge.com/surge-knowledge-base/technotes/dns.md)
- [Testing Strategy for Automatic Policy Groups](https://kb.nssurge.com/surge-knowledge-base/technotes/testing-group.md): The testing strategy for Surge's automatic policy group is quite complex. This document provides a detailed description of the design behavior and rationale under various circumstances.
- [Differences between REJECT Policies](https://kb.nssurge.com/surge-knowledge-base/technotes/reject.md)
- [User Agent Rules](https://kb.nssurge.com/surge-knowledge-base/technotes/user-agent.md)
- [NAT Types](https://kb.nssurge.com/surge-knowledge-base/technotes/nat-type.md)
- [IPv6 RA Override](https://kb.nssurge.com/surge-knowledge-base/technotes/ipv6-ra.md)
- [VM UDP Fast Path](https://kb.nssurge.com/surge-knowledge-base/technotes/udp-fast-path.md)