POP3

Directives

pop3_auth

Syntax	pop3_auth method ...;
Default	ipop3_auth plain;
Context	mail, server

Sets permitted methods of authentication for POP3 clients. Supported methods are:

plain	USER/PASS, AUTH PLAIN, AUTH LOGIN
apop	APOP. In order for this method to work, the password must be stored unencrypted.
cram-md5	AUTH=CRAM-MD5. In order for this method to work, the password must be stored unencrypted.
external	AUTH=EXTERNAL

Plain text authentication methods (USER/PASS, AUTH PLAIN and AUTH LOGIN) are always enabled, though if the plain method is not specified, AUTH PLAIN and AUTH LOGIN will not be automatically included in pop3_capabilities.

pop3_capabilities

Syntax	pop3_capabilities extension ...;
Default	pop3_capabilities TOP USER UIDL;
Context	mail, server

Sets the POP3 protocol extensions list that is passed to the client in response to the CAPA command. The authentication methods specified in the pop3_auth directive (SASL extension) and STLS are automatically added to this list depending on the starttls directive value.

It makes sense to specify the extensions supported by the POP3 backends to which the clients are proxied (if these extensions are related to commands used after the authentication, when Angie transparently proxies the client connection to the backend).