463 Too many forwarded IP addresses
HTTP response status code 463 Too many forwarded IP addresses is unofficial and an AWS Elastic Load Balancer-specific error used to indicate that the load balancer received a HTTP request that included an X-Forwarded-For header with too many IP addresses.
Usage
When the 463 Too many forwarded IP addresses status code is received, the HTTP request includes the X-Forwarded-For header with too many IP addresses. The X-Forwarded-For header is used to help identify the IP address of a client. Because load balancers intercept traffic between clients and servers, the IP address of the HTTP request recorded in the server logs will only contain the IP addresses of the load balancers processing the HTTP request. The X-Forwarded-For header adds the client IP address for the HTTP request to the logs. When a HTTP request reaches a load balancer and the header does not exist, it is automatically added. If instead the header already exists, then the most recent IP address will be appended. The upper limit for the number of IP addresses is 30.
Note
Search engines like Google will not index a URL with 463 response status, and consequently, URLs that have been indexed in the past but are now returning this HTTP status code will be removed from the search results.
Example
In the example, the client sends an HTTP request that includes the X-Forwarded-For header. The server responds with the 463 Too many forwarded IP addresses status code because there are too many addresses.
Request
X-Forwarded-For: 192.168.1.1, …, 192.168.1.35
Response
HTTP/1.1 463
Content-Type: text/html
Content-Length: 186
<html>
<head>
<title>AWS Load Balancer Error</title>
</head>
<body>
<p>Too many IPs included in X-Forwarded-For. Please limit this to 30 and try again.</p>
</body>
</html>
Takeaway
The 463 Too many forwarded IP addresses status code is a client error that is sent by AWS Elastic Load Balancer when the client includes the X-Forwarded-For header in an HTTP request with more than 30 IP addresses specified.