I'm very new in networking and I'm trying to setup my network as follow [ISP Modem/Router/Switch] + --- + {fxp0} [Linux Firewall] {fxp1} + --- + {??} [Cisco Router 1921] {GE 0/0} + --- + [Cisco Switch] + ... Servers {GE 0/1} + --- + [Cisco Switch] + ... Servers My questions are, Since I'm using both GE 0/0 and GE 0/1 ports to connect to switch, how can I connect my Linux Firewall (Port fxp1) to my Cisco Router? I know the USB and Console port are for configuration, can I use AUX port to connect my firewall (if so is it consider a right way)? Is my setup is right? if not can someone please explain to me to do the setup in right way. Link to the picture of my router: Cisco Router 1921 Thanks