The POP3 Extension Mechanism [RFC2449] updates [RFC1939] to define a mechanism to announce support for optional commands, extensions, and unconditional server behavior. Please see Section 1 of [RFC2449] for details regarding POP3 Extensions.
Registries included below
Standards Track or IESG-approved Experimental RFC
CAPA Tag | CAPA Args | Added Cmds | Cmds Affected | List | Diffs | Cmd Valid | References |
---|---|---|---|---|---|---|---|
TOP | none | TOP | none | both | no | TRANSACTION | [RFC2449][RFC1939] |
USER | none | USER, PASS | none | both | no | AUTHENTICATION | [RFC2449][RFC1939] |
SASL | mech list | AUTH | none | both | no | AUTHENTICATION | [RFC2449][RFC5034] |
RESP-CODES | none | none | none | both | no | n/a | [RFC2449] |
LOGIN-DELAY | secs, USER | none | USER, PASS, APOP, AUTH | both | yes | n/a | [RFC2449] |
PIPELINING | none | none | all | both | no | n/a | [RFC2449] |
EXPIRE | days, NEVER, USER | none | none | both | yes | n/a | [RFC2449] |
UIDL | none | UIDL | none | both | no | TRANSACTION | [RFC2449][RFC1939] |
IMPLEMENTATION | text | none | none | TRANS, both | no | n/a | [RFC2449][RFC1939] |
STLS | none | STLS | USER, PASS, CAPA | both | no | AUTHENTICATION | [RFC2595] |
AUTH-RESP-CODE | none | none | none | both | no | n/a | [RFC3206] |
UTF8 | USER | UTF8 | USER, PASS, APOP, LIST, TOP, RETR | both | no | AUTHORIZATION | [RFC6856] |
LANG | none | LANG | all | both | no | AUTHORIZATION TRANSACTION | [RFC6856] |
RFC Specification Required
See Section 9 of [RFC2449] for details regarding Response Codes.
Response Code | Response Types | Commands | Reference |
---|---|---|---|
LOGIN-DELAY | -ERR | USER[1], PASS, APOP, AUTH | [RFC2449] |
IN-USE | -ERR | PASS, APOP, AUTH | [RFC2449] |
SYS/PERM | -ERR | All commands | [RFC3206] |
SYS/TEMP | -ERR | All commands | [RFC3206] |
AUTH | -ERR | Any authentication command including AUTH USER [2], PASS, or APOP. | [RFC3206] |
UTF8 | -ERR | LIST, TOP, RETR | [RFC6856] |
[1] |
see spec for details |
[2] |
Returning the AUTH response code to the USER command reveals to the client that the specified user exists. It is strongly RECOMMENDED that the server not issue this response code to the USER command. |