Although an advanced firewall can do much more than filter packets based on sources and destinations, some threats are most efficiently tackled by complementing the firewall with external content inspection servers (CIS) and external anti-virus gateways. With StoneGate, this integration can be done easily. Just add one rule to the security rule base and activate an agent to redirect the network traffic for inspection server. Agent redirection is truly transparent and does not require any additional configurations on the client machines. For instance, incoming SMTP e-mail traffic could be forwarded from the firewall to the content inspection server for virus and content checking. According to the firewall security rules, content inspection server removes suspicious content and the checked packets are returned back to the firewall for routing to their final destination. Viruses and hazardous content will be discarded before packets enter the internal network. Content inspection server can also be used to control outbound Web traffic. The firewall can redirect traffic to a content inspection server, which examines the destination web address (URL). If the site is on the list of inappropriate sites, traffic is denied. Approved traffic continues as usual.