The Max-Forwards request-header field may be used with the TRACE method (section 14.31) to limit the number of proxies or gateways that can forward the request to the next inbound server. This can be useful when the client is attempting to trace a request chain which appears to be failing or looping in mid-chain.
Max-Forwards = "Max-Forwards" ":" 1*DIGIT
The Max-Forwards value is a decimal integer indicating the remaining number of times this request message may be forwarded.
Each proxy or gateway recipient of a TRACE request containing a Max- Forwards header field SHOULD check and update its value prior to forwarding the request. If the received value is zero (0), the recipient SHOULD NOT forward the request; instead, it SHOULD respond as the final recipient with a 200 (OK) response containing the received request message as the response entity-body (as described in section 9.8). If the received Max-Forwards value is greater than zero, then the forwarded message SHOULD contain an updated Max- Forwards field with a value decremented by one (1).
The Max-Forwards header field SHOULD be ignored for all other methods defined by this specification and for any extension methods for which it is not explicitly referred to as part of that method definition.