Client-IP HTTP header to X-Forwarded-For

Mike lists.accounts at
Thu May 3 21:07:37 MSD 2007

Igor Sysoev wrote:
> On Thu, May 03, 2007 at 03:31:44PM +0100, Mike wrote:
>> Client requests are through virtual IP's that are handled by a hardware 
>> load balancer, and then passed onto the real servers on the backend. The 
>> source IP from the client is NAT'd so that all IP's appear to originate 
>> from the load balancer. Responses from the real servers are sent back 
>> via the load balancer to the client.
>> On the load balancer, I have enabled, in the configuration, that a 
>> header be added by the load balancer and passed onto the server that is 
>> running Nginx (version 0.5.19). The request header that is added and 
>> passed out to the real server, is as follows:
>> Client-IP: myip
>> Is there any way to get Nginx to log this IP as the remote_addr or as 
>> X-Forwarded-For so that the PHP application that Nginx is passing 
>> requests to will log the real source IP? I realise that there have been 
>> posts in the past but I have not been able to figure this out.
> This header is available in nginx as $http_client_ip.
> You can describe it in log_format instead of $remote_ip
> and you pass it to FastCGI:
> fastcgi_param  REMOTE_ADDR        $http_client_ip;

Hi Igor

Thanks for the fast and accurate response.

I did a search against the $http_client_ip string on the wiki and 
nothing showed up, so unless anyone has any objections, I'll add this 
with my use-case scenario.


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