What is the difference between SSL and TLS?

Short answer

SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are the same protocol family that encrypts the connection between the client and the server and verifies the server's identity with a certificate; TLS is the continuation of SSL. The last version of SSL, SSL 3.0, has been deprecated after being found insecure; the versions in use today are TLS 1.2 and TLS 1.3. The name "SSL" lives on out of habit: in TR7, certificates are kept on the SSL/TLS Certificates screen and protocol settings on the TLS Security Profiles screen, and the accepted version range is selected from SSLv3–TLSv1.3 in the Min. SSL Version / Max. SSL Version fields.

Where It Is Used in TR7

Where	Field / label	What for
Certificates & PKI → TLS Security Profiles	Min. SSL Version, Max. SSL Version (SSLv3, TLSv1.0, TLSv1.1, TLSv1.2, TLSv1.3)	The accepted protocol version range
HTTP and L7 TCP vService → Details	SSL Security	Assigning the profile to the vService
Backend Service	Backend SSL Security Profile	The version range TR7 uses when connecting to the Backend Service with TLS
Certificates & PKI → SSL/TLS Certificates	Certificate records	The X.509 certificates presented in the connection
Load Balancer → Conditions (Policy Match)	SSL Version	A decision based on the version the client connected with

Common Misconceptions

• "An SSL certificate and a TLS certificate are different." Both are the same X.509 certificate; which protocol version the connection is established with is determined not by the certificate but by the server's version setting.
• "Since it is in the option list, SSLv3 is secure." SSL 3.0 has been deprecated by RFC 7568, and TLS 1.0 and 1.1 by RFC 8996; the options exist only for old clients.
• "SSL and TLS are managed with separate settings." In TR7, the SSL and TLS versions are in the same Min. SSL Version / Max. SSL Version list; the labels that contain "SSL" (SSL Security, SSL/TLS Certificates) also cover TLS.

How it is done in the documentation

• TLS Security Profiles · What Is a TLS Security Profile?
• TLS Security Profiles · Min. SSL Version
• SSL/TLS Certificates · What Is an SSL/TLS Certificate?

Related questions

• What is the difference between the TLS versions (TLS 1.0, 1.1, 1.2, 1.3)?
• What is a TLS Security Profile, and what does it configure?
• How do I disable TLS 1.0/1.1; is TLS 1.3 supported?
• What is an SSL/TLS certificate?