20-3
Cisco ASDM User Guide
OL-16647-01
Chapter 20 Configuring Access Rules and EtherType Rules
Information About Access Rules and EtherType Rules
Note “Inbound” and “outbound” refer to the application of an access list on an interface, either to traffic
entering the security appliance on an interface or traffic exiting the security appliance on an interface.
These terms do not refer to the movement of traffic from a lower security interface to a higher security
interface, commonly known as inbound, or from a higher to lower interface, commonly known as
outbound.
An outbound access list is useful, for example, if you want to allow only certain hosts on the inside
networks to access a web server on the outside network. Rather than creating multiple inbound access
lists to restrict access, you can create a single outbound access list that allows only the specified hosts
(see Figure 20-1). The outbound access list prevents any other hosts from reaching the outside network.
Figure 20-1 Outbound Access List
Information About Access Rules
This section describes information about access rules, and includes the following topics:
IP Addresses Used for Access Rules When You Use NAT, page 20-4
Access Rules for Returning Traffic, page 20-6
Allowing Broadcast and Multicast Traffic through the Transparent Firewall Using Access Rules,
page 20-6
Web Server:
209.165.200.225
Inside HR Eng
Outside
Static NAT
209.165.201.410.1.1.14
Static NAT
209.165.201.610.1.2.67 Static NAT
209.165.201.810.1.3.34
ACL Outbound
Permit HTTP from 209.165.201.4, 209.165.201.6,
and 209.165.201.8 to 209.165.200.225
Deny all others
132210
ACL Inbound
Permit from any to any
ACL Inbound
Permit from any to any
ACL Inbound
Permit from any to any
Security
appliance