How to see IP address through XG firewall

Question

We have a IIS webserver sitting behind an XG135 firewall. 
 The webserver can no longer see the IP address of clients that connect to it - it only sees the IP address of the firewall. 
 Can the clients' IP addresses be passed through? Perhaps they could be added as a custom HTTP header to their HTTP requests? 
 Chris.

emmosophos · Answer

Hello Chris, 
 Thank you for contacting the Sophos Community. 
 If you are using WAF, there is an option called Pass Host Header, if enabled this should allow you your ISS to see the IP where the request came from. 
 Also for IIS take a look at this https://techcommunity.microsoft.com/t5/iis-support-blog/how-to-use-x-forwarded-for-header-to-log-actual-client-ip/ba-p/873115 since a special header needs to be enabled too. 
 Regards,