Is Http POST limitless?

Question

I heard that POST has no limit in data size it can be send by it, is that true or is there some really high limit?

Answer 1

There is no limit according to the HTTP protocol itself, but implementations will have a practical upper limit. I have sent data exceeding 4 GB using POST to Apache, but some servers did have a limit of 4 GB at the time.

Answer 2

POST allows for an arbitrary length of data to be sent to a server, but there are limitations based on timeouts/bandwidth etc.

I think basically, it's safer to assume that it's not okay to send lots of data.

Answer 3

It rather depends on the web server and web browser:

Internet explorer All versions 2GB-1
Mozilla Firefox All versions 2GB-1
IIS 1-5 2GB-1
IIS 6 4GB-1

Although IIS only support 200KB by default, the metabase needs amending to increase this.

http://www.motobit.com/help/scptutl/pa98.htm

The POST method itself does not have any limit on the size of data.

Answer 4

Different IIS web servers can process different amounts of data in the 'header' as this article points out.

Note that there is no limit on the number of FORM elements you can pass via POST, but only on the aggregate size of all name/value pairs. While GET is limited to as low as 1024 characters, POST data is limited to 2 MB on IIS 4.0, and 128 KB on IIS 5.0. Each name/value is limited to 1024 characters, as imposed by the SGML spec. Of course this does not apply to files uploaded using enctype='multipart/form-data' ... I have had no problems uploading files in the 90 - 100 MB range using IIS 5.0, aside from having to increase the server.scriptTimeout value as well as my patience!

Answer 5

Http may not have an upper limit, but webservers may have one. In asp.net there is a default accept-limit of 4MB, but you (the developer/webmaster) can change that to be higher or lower.