HTTP headers automatically set

Question

I am starting to learn about http correctly.

I am working in lamp stack.

On the command line i am requesting a local page which will be served with apache to see the headers that are returned.

curl -i local.testsite

The page i am requesting has no content and i am not setting any headers but there are already a lot of headers sent in the response such as:

HTTP/1.1 200 OK
Date: Thu, 17 Jan 2013 20:28:52 GMT
Server: Apache/2.2.22 (Ubuntu)
X-Powered-By: PHP/5.3.10-1ubuntu3.4
Vary: Accept-Encoding
Content-Length: 0
Content-Type: text/html

So if i am not setting these, does apache set these automatically?

Yes, apache sets them automatically. You can set that Server: and X-Powered-By: are not by default. — Glavić
– Glavić, Commented Jan 17, 2013 at 20:31

Mike Brant · Accepted Answer · 2013-01-17 20:33:14Z

3

Yes Apache is setting those by default. By the way, if you only care about the headers, you should use

curl -I local.testsite

-I returns the headers only (HTTP HEAD request), such that even if you had content on the page you would only get the header.

answered Jan 17, 2013 at 20:33

Mike Brant

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Community · Accepted Answer · 2021-10-07 05:59:28Z

3

Some are set by PHP:

The X-Powered-By header is set by the expose_php INI setting.
The Content-Type header is set by the default_mimetype INI setting.

The others are set by Apache:

The Server header is set by the ServerSignature directive.
The Vary: Accept-Encoding header is usually sent when mod_deflate is enabled.

Date and Content-Length are not configurable as they are part of the HTTP spec. Date is included as a MUST (except under some conditions) and Content-Length as a SHOULD.

See also How to remove date header from apache? and How to disable the Content-Length response header with Apache?.

edited Oct 7, 2021 at 5:59

CommunityBot

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answered Jan 17, 2013 at 20:32

cmbuckley

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