I use zeroshell b11 for my office
I create as bridge and enable captive portal, http proxy, virus scan, access loging any access and send loging to syslog server
I run zeroshell on vmware
my problem is, I need to reboot zeroshell everyday because, internet in my office not running after reboot internet will come back.
If it is just a matter of keeping the connection alive ZS has an integrated feature. Go to Network-> Netbalancer and on the right side boxes enable ICMP failover checking. Below enter some pingable IP addresses (e.g http://www.yahoo.com).