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Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter8 Completing Interface Configuration (Routed Mode)
Monitoring Interfaces
If you enable same security interface communication, you can still configure interfaces at different
security levels as usual.

Information About Intra-Interface Communication

Intra-interface communication might be useful for VPN traffic that enters an interface, but is then routed
out the same interface. The VPN traffic might be unencrypted in this case, or it might be reencrypted for
another VPN connection. For example, if you have a hub and spoke VPN network, where the ASA is the
hub, and remote VPN networks are spokes, for one spoke to communicate with another spoke, traffic
must go into the ASA and then out again to the other spoke.
Note All traffic allowed by this feature is still subject to firewall rules. Be careful not to create an asymmetric
routing situation that can cause return traffic not to traverse the ASA.
Detailed Steps
Monitoring Interfaces
To monitor interfaces, enter one of the following commands:
Configuration Examples for Interfaces in Routed Mode
This section includes the following topics:
ASA 5505 Example, page8-16

ASA 5505 Example

The following example configures three VLAN interfaces for the Base license. The third home interface
cannot forward traffic to the business interface.
hostname(config)# interface vlan 100
Command Purpose
same-security-traffic permit
inter-interface
Enables interfaces on the same security level so that they can communicate
with each other.
same-security-traffic permit
intra-interface
Enables communication between hosts connected to the same interface.
Command Purpose
show interface Displays interface statistics.
show interface ip brief Displays interface IP addresses and status.