14 Header Field Definitions

This section defines the syntax and semantics of all standard HTTP/1.1 header fields. For entity-header fields, both sender and recipient refer to either the client or the server, depending on who sends and who receives the entity.

1.      Accept ... 14.1

2.      Accept-Charset ... 14.2

3.      Accept-Encoding ... 14.3

4.      Accept-Language ... 14.4

5.      Accept-Ranges ... 14.5

6.      Age ... 14.6

7.      Allow ... 14.7

8.      Authorization ... 14.8

9.      Cache-Control ... 14.9

1.

What is Cacheable ... 14.9.1

2.

What May be Stored by Caches ... 14.9.2

3.

Modifications of the Basic Expiration Mechanism ... 14.9.3

4.

Cache Revalidation and Reload Controls ... 14.9.4

5.

No-Transform Directive ... 14.9.5

6.

Cache Control Extensions ... 14.9.6

10.

Connection ... 14.10

11.

Content-Encoding ... 14.11

12.

Content-Language ... 14.12

13.

Content-Length ... 14.13

14.

Content-Location ... 14.14

15.

Content-MD5 ... 14.15

16.

Content-Range ... 14.16

17.

Content-Type ... 14.17

18.

Date ... 14.18

1.

Clockless Origin Server Operation ... 14.18.1

19.

ETag ... 14.19

20.

Expect ... 14.20

21.

Expires ... 14.21

22.

From ... 14.22

23.

Host ... 14.23

24.

If-Match ... 14.24

25.

If-Modified-Since ... 14.25

26.

If-None-Match ... 14.26

27.

If-Range ... 14.27

28.

If-Unmodified-Since ... 14.28

29.

Last-Modified ... 14.29

30.

Location ... 14.30

31.

Max-Forwards ... 14.31

32.

Pragma ... 14.32

33.

Proxy-Authenticate ... 14.33

34.

Proxy-Authorization ... 14.34

35.

Range ... 14.35

1.

Byte Ranges ... 14.35.1

2.

Range Retrieval Requests ... 14.35.2

36.

Referer ... 14.36

37.

Retry-After ... 14.37

38.

Server ... 14.38

39.

TE ... 14.39

40.

Trailer ... 14.40

41.

Transfer-Encoding ... 14.41

42.

Upgrade ... 14.42

43.

User-Agent ... 14.43

44.

Vary ... 14.44

45.

Via ... 14.45

46.

Warning ... 14.46

47.

WWW-Authenticate ... 14.47