ALPN Protocol ID Reference
All registered ALPN protocol identifiers — h2, h3, http/1.1 and more.
| ALPN ID | Description |
|---|---|
| http/1.1 | HTTP/1.1 |
| h2 | HTTP/2 over TLS |
| h2c | HTTP/2 over cleartext (rarely seen via ALPN) |
| h3 | HTTP/3 over QUIC |
| h3-29 | HTTP/3 draft 29 (legacy) |
| h3-32 | HTTP/3 draft 32 (legacy) |
| hq | HTTP-over-QUIC (deprecated experimental) |
| hq-interop | QUIC interop draft |
| spdy/3.1 | SPDY 3.1 (deprecated) |
| ftp | FTP |
| imap | IMAP |
| pop3 | POP3 |
| managesieve | Sieve management |
| acme-tls/1 | ACME TLS-ALPN-01 challenge |
| ntske/1 | NTS Key Exchange |
| dot | DNS over TLS |
| doq | DNS over QUIC |
| xmpp-client | XMPP client-to-server |
| xmpp-server | XMPP server-to-server |
| postgresql | PostgreSQL frontend protocol |
| smb | SMB / CIFS |
About this tool
Application-Layer Protocol Negotiation IDs used during the TLS handshake. Helps interpret tcpdump / Wireshark output and choose what to negotiate.