Stop ISDN T1 PRI from dialing remotes.

[4DeanB]

Hello People and thanks for taking a look at my post. I installed a 2651 with a channelized T1 PRI controller, configured as 23 ISDN channels. The remote 804s dial the PRI just fine and everyone was happy until the first phone bill arrived. It seems that the phone company gave the customer a decent flat rate plan for the remote ISDNs initiating calls to the Host PRI, but not for the PRI to dial out to the remote ISDNs. sh isdn history shows the Host network contacting the remotes for unknown reasons for extended periods, therefore racking up the bill. I don't care about the traffic trying to call the remotes, it's not necessary. Only the remotes need to dial the PRI. How can I disable the T1 PRI from initiating calls out? The system is live, I'm not very experienced with the set-up and I can't afford to guess and experiment. Is it as simple as: dialer-list 1 protocol ip deny? Or will that deny the inbounds as well?

sh run
Building configuration...

Current configuration : 1957 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname ABC
!
enable secret xxxxxxx
!
username tom password 0 xxxxx
username dick password 0 xxxxx
username harry password 0 xxxxx
.
.
.
.
.

ip subnet-zero
!
!
!

isdn switch-type primary-ni
!
controller T1 1/0
framing esf
linecode b8zs
pri-group timeslots 1-24
!
!
!
interface Loopback0
ip address 10.11.11.1 255.255.255.0
!
interface FastEthernet0/0
ip address 192.168.59.254 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface Serial1/0:23
no ip address
encapsulation ppp
dialer rotary-group 0
dialer-group 1
isdn switch-type primary-ni
ppp authentication chap callin
ppp multilink
!
interface Dialer0
ip address 192.168.159.1 255.255.255.0
encapsulation ppp
dialer in-band
dialer map ip 192.168.159.2 name tom 9545551212
dialer map ip 192.168.159.3 name dick 9545551313
dialer map ip 192.168.159.4 name harry 9545551414
dialer-group 1
no peer default ip address
ppp authentication chap callin
ppp multilink
!
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.59.245
ip route 10.59.2.0 255.255.255.0 192.168.159.2
ip route 10.59.3.0 255.255.255.0 192.168.159.3
ip route 10.59.4.0 255.255.255.0 192.168.159.4

ip http server
ip pim bidir-enable
!
!
dialer-list 1 protocol ip permit
!
line con 0
line aux 0
line vty 0 4
password xxxxxx
login
!
!
end

 

[Frenchie2069]

The dialer-list command defines the "interesting" traffic for the dialer interface. To prevent it dialing you should do:

no dialer-list 1

This will not prevent it from receiving calls.

HTH,
Michael.

 

[jimmyzz]

4DeanB,
If you dont want this router to call the remote sites, remove the lines from your Dialer0 profile which specify the remote site ISDN ph number:
dialer map ip 192.168.159.2 name tom 9545551212
dialer map ip 192.168.159.3 name dick 9545551313
dialer map ip 192.168.159.4 name harry 9545551414

Replace the with:
dialer remote-name tom
dialer remote-name dick
dialer remote-name harry

This way it knows the remote sites to accept the calls from but does not know how to contact them.

I'd set up a seperate dialer profile for each remote site. Let me know if you need help with doing this.

JimmyZ

 

[4DeanB]

Thanks for the prompt responses frenchie and jimmyz. Frenchie, you stated that removing dialer-list 1 will not prevent it from connecting inbound calls, but jimmyz, you say that I'd be better off modifying the Dialer0 config so that my 2651 recognizes the inbound remote callers. Is there a contradiction here or will both methods work? just different approaches?

After further thought, maybe I need to specify custom interesting traffic, so that I can verify connectivity from my PC in Florida to the 2651 in Virginia and then out to these remotes. If I totally turn off the ability of the PRI to dial out, will I have any other method to reach the 804s? Can I specify telnet from the 2651 to an 804 as interesting traffic? Thanks guys for your help.

 

[jimmyzz]

4DeanB,
There are usually many ways to "skin a cat", like wise there are different approaches to solving problems on a cisco router. My approach follows the logic, if your c2651 does not know the phone numbers of your remote sites, then how will it be able to initiate a call to the remote site. All it needs to know is the name of your remote-site router so it can "authenticate" it. If you want your remote site to initiate the call, then only the remote site needs to define the destination PRI number.

I have not applied Frenchie's method before, but I was under the assumption you still had to define interesting traffic for INcoming calls. Frenchie, is there a cisco doc on this. Would be "interesting" (pardon the punto read more about this.

JimmyZ