[H] Use a router as a switch

[Winterlight]

I have a  8 port 10/100wired Linksys router that I am not using but 
would like to use as a plain switch.

 I turned off DHCP on the router and ran a CAT5e from a standard 
port on my actual router to  the number one port of this 
router(switch). I have nothing plugged into the WAN port of the 
router I want to use as a switch.

Zone alarm, which is installed on the members of the LAN immediately 
see the new router/switch as a new network. If they saw it as a plain 
switch, like the Dlink Switch I am currently using then they wouldn't 
identify it.

 Is there a way  I can make this router into a switch so as the 
software firewalls won't treat it as a router?