1. Home
  2. Cisco Systems
  3. Unidirectional Isdn connectivity

Unidirectional Isdn connectivity

Hi,

I configured a pair of Cisco 800 routers to connect 2 networks bia an Isdn Bri link. Below a summary of the configurations and everything is working like a charm. I need now to change the configuration a little bit so that the call is allowed only when the router A calls the router B but not viceversa. How can I configure the router A to disallow calls from B?

Thank you in advance! Diego.

--------------------------------------

Router A configuration summary:

username RouterB password 0 xxxxxxxx ! interface BRI0 encapsulation ppp dialer pool-member 1 isdn switch-type basic-net3 ! interface Dialer0 ip address 172.31.63.190 255.255.255.252 encapsulation ppp dialer remote-name RouterB dialer pool 1 dialer idle-timeout 300 dialer string 12345678 dialer-group 1 ppp authentication chap ! ip route 192.168.1.0 255.255.255.255 Dialer0 ! access-list 101 permit ip any any dialer-list 1 protocol ip list 101

------------------------------------------------------

Router B configuration summary:

username RouterA password 0 xxxxxxxx ! interface BRI0 encapsulation ppp dialer pool-member 1 isdn switch-type basic-net3 ppp authentication chap ! interface Dialer0 ip address 172.31.63.189 255.255.255.252 encapsulation ppp dialer pool 1 dialer remote-name RouterA dialer idle-timeout 300 dialer string 87654321 dialer-group 1 ppp authentication chap ! ip route 10.103.165.0 255.255.255.0 Dialer0 ! access-list 101 permit ip any any dialer-list 1 protocol ip list 101

Reply to
Diego B.
Loading thread data ...

You should actually reconfigure your router B. Just remove 'dialer string ...' statement and it won't be able to call...

Reply to
Ivan Ostreš

Thank you Ivan,

you are right, but my question is a little bit different. The routers A and B are actually administered by different companies and the administrator of routerA has to decide when the link could be established (the reason depends on his security policy). So we need to configure the router A to disallow the call coming from B, as the router A is the only one allowed to establish the link. In other words, it's the configuration of router A controlling the issue. Have you any suggestion on how to implement this?

Thank you again! Diego.

Reply to
Diego B.

Thank you Ivan,

you are right, but my question is a little bit different. The routers A and B are actually administered by different companies and the administrator of routerA has to decide when the link could be established (the reason depends on his security policy). So we need to configure the router A to disallow the call coming from B, as the router A is the only one allowed to establish the link. In other words, it's the router A that has to disallow the incoming calls and not the router B that avoids to call.

Have you any suggestion on how to implement this?

Thank you again! Diego.

Reply to
Diego B.

If you receive caller ID, I would try fixing it like that (lookup for command on

formatting link
If you do not get CLID, then you can allways set a password to router A so router B would be unable to auhenticate which should eventualy drop the connection.

Reply to
Ivan Ostreš

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.