Chapter 19 Managing the AIP SSM and CSC SSM
Managing the CSC SSM
•Incoming SMTP connections destined to inside mail servers.
In Figure
Figure
Security
appliance
192.168.10.0
inside
outside | 192.168.30.0 | Internet |
|
192.168.20.0
(dmz)
143800
Web server | Mail server |
There are many ways you could configure the adaptive security appliance to identify the traffic that you want to scan. One approach is to define two service policies, one on the inside interface and the other on the outside interface, each with an access list that matches traffic to be scanned. The following access list could be used on the policy applied to the inside interface:
As previously mentioned, policies applying the csc command to a specific interface are effective on both ingress and egress traffic, but by specifying 192.168.10.0 as the source network in the csc_out access list the policy applied to the inside interface matches only connections initiated by the hosts on the inside network. Notice also that the second ACE of the access list uses the deny keyword. This ACE does not mean the adaptive security appliance blocks traffic sent from the 192.168.10.0 network to TCP port 80 on the 192.168.20.0 network. It simply exempts the traffic from being matched by the policy map and thus prevents the adaptive security appliance from sending it to the CSC SSM.
You can use deny statements in an access list to exempt connections with trusted external hosts from being scanned. For example, to reduce the load on the CSC SSM, you might want to exempt HTTP traffic to a well known, trusted site. If the web server at such a site had the IP address 209.165.201.7, you could add the following ACE to the csc_out access list to exclude HTTP connections between the trusted external web server and inside hosts from being scanned by CSC SSM:
The second policy in this example, applied to the outside interface, could use the following access list:
| Cisco Security Appliance Command Line Configuration Guide |
|
