Apache Reference: http_core, LimitRequestFields
Limit Maximum Number of Request Fields
Syntax: LimitRequestFields A
Example: LimitRequestFields 20
Since: Apache 1.3
The directive specifies the maximum number of header fields that can appear in a request message. The number argument is an integer from 0 (meaning unlimited) to 32,767 (32 KB). The directive allows a server administrator to modify the limit on the number of request header fields allowed in an HTTP request. This value should be larger than the number of fields that a normal client request might include. Use of this directive gives the server administrator greater control over abnormal client request behavior, which help prevent some forms of denial-of-service attacks.