Shutdown "lo" To Test Firewall

From: Buck Turgidson (jc_va_at_hotmail.com)
Date: 11/24/04 

Date: Tue, 23 Nov 2004 20:59:31 -0500

It is my understanding, perhaps incorrect, that I cannot test connectivity
and firewall rules from inside my network because of the loopback interface.
If I shut this down, and access my linux box using it's external IP, will
this be a valid test?

Do I just type "ifconfig lo down" ?

Thanks.