Protocol Version Selection and Management

Modern SSL/TLS deployments should exclusively use TLS 1.2 and TLS 1.3, disabling all SSL versions and older TLS versions. SSL 2.0 and 3.0 contain fundamental security flaws that enable attacks like POODLE. TLS 1.0 and 1.1, while more secure than SSL, have known weaknesses and face deprecation across the industry. Major browsers have removed or plan to remove support for these older protocols, making their continued use both insecure and impractical.

TLS 1.3 represents the current gold standard, offering improved security and performance over previous versions. The protocol removes vulnerable features, mandates forward secrecy, and reduces handshake latency. Organizations should enable TLS 1.3 wherever possible, as client support has reached critical mass. The simplified cipher suite negotiation in TLS 1.3 also reduces configuration complexity.

Protocol configuration requires attention to both minimum and maximum versions. Setting minimum versions too low exposes systems to downgrade attacks, where attackers force connections to vulnerable protocols. Conversely, setting requirements too strictly might exclude legitimate users with older devices. Organizations should analyze their user base to determine acceptable minimums, typically TLS 1.2 for broad compatibility.

Testing protocol configurations ensures intended behavior across different clients. Tools like nmap's ssl-enum-ciphers script identify supported protocols and cipher suites. Regular testing catches configuration drift and validates that disabled protocols remain disabled. Monitoring connection logs reveals actual protocol usage, helping identify when older protocol support can be safely removed.