Appendix B. Command Index
Alphabetical Command List
| Command | Section | Page | Type |
|---|---|---|---|
| APOP | 7 | - | Optional |
| DELE | 5 | - | Minimal |
| LIST | 5 | - | Minimal |
| NOOP | 5 | - | Minimal |
| PASS | 7 | - | Optional |
| QUIT | 4, 6 | - | Minimal |
| RETR | 5 | - | Minimal |
| RSET | 5 | - | Minimal |
| STAT | 5 | - | Minimal |
| TOP | 7 | - | Optional |
| UIDL | 7 | - | Optional |
| USER | 7 | - | Optional |
Commands by State
AUTHORIZATION State
- APOP (optional)
- PASS (optional)
- QUIT (minimal)
- USER (optional)
TRANSACTION State
- DELE (minimal)
- LIST (minimal)
- NOOP (minimal)
- RETR (minimal)
- RSET (minimal)
- STAT (minimal)
- TOP (optional)
- UIDL (optional)
UPDATE State
- QUIT (minimal)
Command Categories
Minimal Commands (Required)
All POP3 servers MUST implement these commands:
- STAT, LIST, RETR, DELE, NOOP, RSET, QUIT
Optional Commands (Recommended)
Servers SHOULD implement these for better functionality:
- USER, PASS, APOP, TOP, UIDL
Implementation Notes:
- Minimal POP3 Server: Must implement all minimal commands plus at least one authentication method
- Full POP3 Server: Should implement both minimal and optional commands
- Authentication: At least one of USER/PASS or APOP must be supported