SNI
SNI (Server Name Indication, RFC 6066) carries the target hostname during the TLS handshake so that multiple HTTPS virtual hosts on one IP can pick the right certificate.
Purpose
It passes the hostname in the ClientHello so a server hosting many virtual hosts can select the matching certificate.
Mechanism
The ClientHello carries an SNI extension with the target hostname, and the server returns the matching certificate from its collection. Without SNI the server can only present a default certificate, making multi-virtual-host HTTPS impractical.
Use cases
- HTTPS virtual hosting
- CDN multi-domain hosting
- Cloud TLS
Related tools
HTTP Status Codes
Reference table of common HTTP status codes (1xx-5xx) with names, categories, and descriptions. Free, private, and 100% client-side. TOOL
URL Parser
Parse a URL into its components: protocol, host, path, query, hash, port, username, and password. Free, private, and 100% client-side. TOOL