Rewrite HTTP host based on server name loadbalanced

Hello Jean.

I would say that "LB::server addr" is not a valid method to use in this event (HTTP_REQUEST_SEND) base on this -> https://clouddocs.f5.com/api/irules/LB__server.html

I recommend you to use "IP::server_addr" instead. I'm also including some log events to trace the iRule variables. You can remove those logs after verify that everything is working properly.

when HTTP_REQUEST_SEND {
	clientside {
		log local0. "[IP::client_addr]:[TCP::client_port]: [HTTP::method] request to [HTTP::host][HTTP::uri]"
		if {[HTTP::host] equals "bi.test.com"} {
			set host_header_value [class match -value [IP::server_addr] equals test-datagroup]
			log local0. "[IP::client_addr]:[TCP::client_port]: Looked up [IP::server_addr], found: $host_header_value."
			if {$host_header_value ne ""}{
				HTTP::header replace Host $host_header_value
				log local0. "[IP::client_addr]:[TCP::client_port]: Replaced Host header with $host_header_value."
			}
		}
	}
}

REF - https://devcentral.f5.com/s/articles/rewrite-host-header-to-server-name

KR,

Dario.