Maximum on http header values?

http http-headers
Cory picture Cory · Mar 26, 2009 · Viewed 295.2k times · Source

Is there an accepted maximum allowed size for HTTP headers? If so, what is it? If not, is this something that's server specific or is the accepted standard to allow headers of any size?

Answer

vartec picture vartec · Mar 26, 2009

No, HTTP does not define any limit. However most web servers do limit size of headers they accept. For example in Apache default limit is 8KB, in IIS it's 16K. Server will return 413 Entity Too Large error if headers size exceeds that limit.

Related question: How big can a user agent string get?

Related questions

application/x-www-form-urlencoded or multipart/form-data?

In HTTP there are two ways to POST data: application/x-www-form-urlencoded and multipart/form-data. I understand that most browsers are only able to upload files if multipart/form-data is used. Is there any additional guidance when to use one of …

Read More
How do we control web page caching, across all browsers?

Our investigations have shown us that not all browsers respect the HTTP cache directives in a uniform manner. For security reasons we do not want certain pages in our application to be cached, ever, by the web browser. This must …

Read More
Accessing the web page's HTTP Headers in JavaScript

How do I access a page's HTTP response headers via JavaScript? Related to this question, which was modified to ask about accessing two specific HTTP headers. Related: How do I access the HTTP request header fields via JavaScript?

Read More