Firewall client; with or without NAT?

Hi everybody! Anyone please help me in my problem by answering my questions.

Do machines installed with the firewall client work without NAT? And, is the machine accessible from external computers by its public IP address? Will the external Webserver see the IP adress of the internal machine (installed with the firewall client), say for example in the log file of the web server?

Thank you very much in advance.