D-Link DFL-2500 User Guide - Page 130

14.1. Overview 111 14.1.2 Action types When all the fields listed in the previous section are matched by a packet, a rule is triggered, and certain action specified by the matching rule will be carried out. The types of actions include: ◦ Allow: Lets the packet pass through the firewall. The firewall will also set up a 'state' to remember the connection, and pass the rest of the packets in this connection through its stateful inspection engine. ◦ NAT: Works like Allow rules, but with dynamic address translation enabled. (See 14.2.2 NAT) ◦ FwdFast: Lets the packet pass through the firewall without setting up a state for it. Generally speaking, it is faster for an individual packet, but it is less secure than Allow or NAT rules, and also slower than Allow rules for the whole established connection, as every subsequent packet also needs to be checked against the rule section. ◦ SAT: Tells the firewall to perform static address translation. (See 14.2.3 Static Address Translation) This rule also requires a matching Allow, NAT or FwdFast rule further down. (See Example) ◦ Drop: Tells the firewall to immediately discard the packet. ◦ Reject: Acts like Drop, but will return a TCP-RST or ICMP-Unreachable message, telling the sender that the packet was disallowed. D-Link Firewalls User's Guide