The simplest firewall is a packet filter with a ACL To allow a gaming server to use port 3535 an exception must be created on a firewall Any packet not filtered by firewall rules a firewall is allowed Firewall slow network traffic A firewall that does stateful packet inspection looks inside packet contents If a connection to a remote office on a high port always times out, then the firewall is most likely at fault. Both a corporate firewall and a personal firewall should be used