| Message Format | Status Codes | URIs | IRIs | Basic Rules | Headers |
| Accept | Accept‑Credentials | Accept‑Encoding | Accept‑Language | Accept‑Ranges | Allow | Authentication‑Info | Authorization | Bandwidth | Blocksize | Cache‑Control | Connection | Connection‑Credentials | Content‑Base | Content‑Encoding | Content‑Language | Content‑Length | Content‑Location | Content‑Type | CSeq | Date | Expires | From | If‑Match | If‑Modified‑Since | If‑None‑Match | Last‑Modified | Location | Media‑Properties | Media‑Range | MTag | Notify‑Reason | Pipelined‑Requests | Proxy‑Authenticate | Proxy‑Authentication‑Info | Proxy‑Authorization | Proxy‑Require | Proxy‑Supported | Public | Range | Referrer | Request‑Status | Require | Retry‑After | RTP‑Info | Scale | Seek‑Style | Server | Session | Speed | Supported | Terminate‑Reason | Timestamp | Transport | Unsupported | User‑Agent | Via | WWW‑Authenticate |