Apache Reference: http_core, LimitRequestLine
LimitRequestLine
Limit Maximum Size of Request Lines
Syntax: LimitRequestLine A
Example: LimitRequestLine 200
Since: Apache 1.3
This directive specifies the maximum size of an HTTP request line. The bytes argument must be an integer size (in bytes) ranging from 0 to 8,190. Use of this directive allows the server administrator to reduce the allowed size of a client's HTTP request line below the normal input buffer size compiled with the server. Because the request line consists of the HTTP method, URL, and protocol version, the LimitRequestLine directive places a restriction on the length of the URL allowed for a request on the server.
This value should be large enough to hold any of the resource names, including any information that might be passed in the query part of a
GETrequest. Use of this directive gives a server administrator greater control over abnormal client request behavior, which help prevent some forms of denial-of-service attacks.