A method for protecting firewall load balancers from a denial of service
attack is provided. Packets are received by the firewall load balancer.
Each packet has a source and a destination. The firewall load balancer is
equipped with a connection database that can contain entries about the
packets. Upon receipt of a packet, the connection database is queried to
determine whether or not there is an entry for the received packet. If an
entry is found in the database, the packet is forwarded to its
destination. Otherwise, if the packet was received from a firewall, then
a new connection entry for the packet is built and is saved to the
connection database and the packet is forwarded on to its destination. If
the packet does not have an entry (match) in the connection database and
the packet was not received from a firewall, then the packet is forwarded
to a firewall.