We currently have 2 ASA 5520s running in Active/Standby failover. We have all 4 NICs being used (Internal, External, DMZ, Failover) on each device and are looking to add another ISP for a backup (using route tracking). The problem i have is there are no more NICs available. I guess I can pruchase the 4 port NIC modules, but they are like $5k each. I could also purchase a layer 2 switch and trunk it to the ASA external interface and separate the external VLANs out that way on the ASA. Im just wondering if anyone has run into this before and what they think the best route to take is in doing this.