A stateful firewall filter inspects traffic flowing between a trusted network and an untrusted network. In contrast to a stateless firewall filter that inspects packets in isolation, a stateful firewall filter provides an extra layer of security by using state information derived from past communications and other applications to make dynamic control decisions.
On the Services Router you can configure Network Address Translation (NAT) either independently or with a stateful firewall filter. For information on configuring NAT independently, see Configuring NAT.
You can use either J-Web Quick Configuration or a configuration editor to configure stateful firewall filters and NAT.
This chapter contains the following topics. For more information about stateful firewall filters and NAT, see the JUNOS Services Interfaces Configuration Guide. To configure a stateless firewall filter, see Configuring Stateless Firewall Filters.