Cisco 5505 - ASA Firewall Edition Bundle, Cli Configuration Manual

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1-5
Cisco ASA Series CLI Configuration Guide
Chapter 1 Configuring Inspection for Management Application Protocols
GTP Inspection
Step 7
To configure parameters that affect the inspection engine, perform the following steps:
a.
To enter parameters configuration mode, enter the following command:
hostname(config-pmap)# parameters
hostname(config-pmap-p)#
The mnc network_code argument is a two or three-digit value identifying the network code.
By default, the security appliance does not check for valid MCC/MNC combinations. This command
is used for IMSI Prefix filtering. The MCC and MNC in the IMSI of the received packet is compared
with the MCC/MNC configured with this command and is dropped if it does not match.
This command must be used to enable IMSI Prefix filtering. You can configure multiple instances
to specify permitted MCC and MNC combinations. By default, the ASA does not check the validity
of MNC and MCC combinations, so you must verify the validity of the combinations configured. To
find more information about MCC and MNC codes, see the ITU E.212 recommendation,
Identification Plan for Land Mobile Stations .
b.
To allow invalid GTP packets or packets that otherwise would fail parsing and be dropped, enter the
following command:
hostname(config-pmap-p)# permit errors
By default, all invalid packets or packets that failed, during parsing, are dropped.
c.
To enable support for GSN pooling, use the permit response command.
If the ASA performs GTP inspection, by default the ASA drops GTP responses from GSNs that were
not specified in the GTP request. This situation occurs when you use load-balancing among a pool
of GSNs to provide efficiency and scalability of GPRS.
You can enable support for GSN pooling by using the permit response command. This command
configures the ASA to allow responses from any of a designated set of GSNs, regardless of the GSN
to which a GTP request was sent. You identify the pool of load-balancing GSNs as a network object.
Likewise, you identify the SGSN as a network object. If the GSN responding belongs to the same
object group as the GSN that the GTP request was sent to and if the SGSN is in a object group that
the responding GSN is permitted to send a GTP response to, the ASA permits the response.
d.
To create an object to represent the pool of load-balancing GSNs, perform the following steps:
Use the object-group command to define a new network object group representing the pool of
load-balancing GSNs.
hostname(config)# object-group network GSN-pool-name
hostname(config-network)#
For example, the following command creates an object group named gsnpool32:
hostname(config)# object-group network gsnpool32
hostname(config-network)#
e.
Use the network-object command to specify the load-balancing GSNs. You can do so with one
network-object command per GSN, using the host keyword. You can also using network-object
command to identify whole networks containing GSNs that perform load balancing.
hostname(config-network)# network-object host IP-address
For example, the following commands create three network objects representing individual hosts:
hostname(config-network)# network-object host 192.168.100.1
hostname(config-network)# network-object host 192.168.100.2
hostname(config-network)#
network-object host 192.168.100.3
hostname(config-network)#