ADTRAN AOS Version R10.1.0 Command Reference Manual page 1001

Command Reference Guide Global Configuration Mode Command Set
Packet Flow:
Case 1: Packets from interfaces with a configured policy class to any other interface
IPv4 ACPs are applied when packets are received on an interface. If an interface has not been assigned a
policy class, by default it will allow all received traffic to pass through. If an interface has been assigned a
policy class, but the firewall has not been enabled with the ip firewall command, traffic will flow normally
from this interface with no firewall processing.
Case 2: Packets that travel in and out a single interface with a configured policy class
These packets are processed through the IPv4 ACPs as if they are destined for another interface (identical
to Case 1).
Case 3: Packets from interfaces without a configured policy class to interfaces with one policy
class
These packets are routed normally and are not processed by the IPv4 firewall. The ip firewall command
has no effect on this traffic.
Case 4: Packets from interfaces without a configured policy class to other interfaces without a
configured policy class
This IPv4 traffic is routed normally. The ip firewall command has no effect on this traffic.
Attack Protection:
When the ip firewall command is enabled, IPv4 firewall attack protection is enabled. AOS blocks traffic
(matching patterns of known networking exploits) from traveling through the device. For some of these
attacks, the user may manually disable checking/blocking while other attack checks are always on anytime
the firewall is enabled.
60000CRG0-35E Copyright © 2012 ADTRAN, Inc. 1001