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Can you trust X-Forwarded-For?
The X-Forwarded-For header is usually set by a proxy, but it can also be added by an attacker. There are some configurations where the X-Forwarded-For header can be trusted, for example if it is set by a reverse proxy on the same host as the web application.
What is X forwarded in IIS?
The X-Forwarded-For (XFF) HTTP header field is a standard method for identifying the originating IP address of a client connecting to a server through the Kemp LoadMaster or any proxy.
What is X forwarded host header?
The X-Forwarded-Host (XFH) header is a de-facto standard header for identifying the original host requested by the client in the Host HTTP request header. Therefore the user’s privacy must be kept in mind when deploying this header.
What is remote address HTTP header?
REMOTE_HOST pertains to the hostname of the client (i.e. the computer making the request). REMOTE_ADDR refers to the IP address of the client. There would be times when the hostname is unresolvable so the REMOTE_HOST will return the REMOTE_ADDR or the IP address instead.
What is proxy address forwarding?
Forward proxies They store and forward Internet services (like the DNS, or web pages) to reduce and control the bandwidth used by the group. Forward proxies can also be anonymous proxies and allow users to hide their IP address while browsing the Web or using other Internet services.
Can I block the true IP address using X-Forwarded-For header?
All the traffic gets to my IIS server through a proxy. I can’t block or white list IP addresses because all the traffic comes from the proxy’s IP address. Can I use the X-Forwarded-For header with IIS?
When to use the X-Forwarded-For request header?
When traffic is intercepted between clients and servers, server access logs contain the IP address of the proxy or load balancer only. To see the original IP address of the client, the X-Forwarded-For request header is used.
Can I block the true IP address with IIS?
I can’t block or white list IP addresses because all the traffic comes from the proxy’s IP address. Can I use the X-Forwarded-For header with IIS? I would proceed with caution using a HTTP header for IP filtering considering they can be controlled by the client unless your webserver takes this in account when it forwards your request.
Can you deny access if X Forwarded For matches IP block?
Deny access if either REMOTE_ADDR or X-Forwarded-For matches the IP block. This also makes it harder for somebody to circumvent the block by using a proxy. If this is not possible, the application should be configured to either trust or ignore the X-Forwarded-For header.