ISDN Security


ISDN technology provides some limited security features and, as previously mentioned, SS7 Q.931's frame provides caller ID information and the dialed number identification service (DNIS). Based on this information, two security solutions are available:

  • Caller ID screening By using the isdn caller interface command, you can define a set of caller telephone numbers that are eligible to make calls to the router. IOS provides additional features, such as exact match and prefix match, where wildcard x can also be used. Unmatched calls are rejected.

  • Called-party number verification The router can be configured to verify the called-party number and the subaddress provided by the switch as part of the SETUP message by using one of the following configurations:

     804-isdn(config-if)#isdn answer 1 804-isdn(config-if)#isdn answer 2 

    Configuration commands for the BRI interface enable you to configure the called-party number, subaddress number, or both. If these numbers are not defined, the router accepts all incoming calls. This feature ensures that for one local loop with multiple ISDN devices, the correct ISDN device accepts and handles the call. For more details, visit Cisco.com.




Troubleshooting Remote Access Networks CCIE Professional Development
Troubleshooting Remote Access Networks (CCIE Professional Development)
ISBN: 1587050765
EAN: 2147483647
Year: 2002
Pages: 235

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