Registry Included Below
| Range | Registration Procedures |
|---|---|
| Options whose names do not begin with "vnd." | Standards Action or IESG-approved experimental RFC |
| Options with "vnd." | First Come First Served |
| Option Identifier | Option Parameters | Added Commands | Standard Commands Affected | Specification Reference | Discussion |
|---|---|---|---|---|---|
| STARTTLS | none | STARTTLS | none | [RFC3887] | see [RFC3887] |