Confusing ISDN backup making calls.

Unanswered Question
Jan 30th, 2007

Hi,

I used to have an interface configured on Router A:

interface Serial2/0:2

description <cct & location>

bandwidth 1024

backup interface Dialer3

ip address <removed>

no ip redirects

no ip unreachables

no ip proxy-arp

DIALER 3 still exists.

The connection has been moved to ROUTER B and a floating static added to ROUTER A to use DIALER 3 on that router.

interface Serial1/2

description <cct & location>

bandwidth 1024

ip address <removed>

no ip redirects

no ip unreachables

no ip proxy-arp

end

ip route xxx.xx.x.0 255.255.255.0 xxx.xx.xxx.xxx 240 name site-backup

The only that has changed is that I removed the configs for interface Serial2/0:2 on ROUTER A and replaced it with another client's information.

What could be wrong? Somehow the ISDN backup is activating and making 1sec calls. I have shutdown DIALER 3 on ROUTER A but I cannot see the problem.

Ideas anyone? The static was missing and I readded it. This did not fix the problem. Should I be checking the remote site where the dialup it made to?

I have this problem too.
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cmccready Tue, 01/30/2007 - 12:16

I'm not sure if i'm seeing everything correctly but is it possible that some routing protocol traffic is bringing up the connection?

bradlesliect Tue, 01/30/2007 - 13:10

It could be but how do I start troubleshooting and where do I start looking?

We make use of BGP, could this be the problem?

Richard Burts Tue, 01/30/2007 - 19:46

Brad

I confess that I find your explanation a bit confusing. If you could provide specifics of the configuration it would help us understand and to find answers to your problem.

While waiting for more detail here is a thought: the original config kept the dialer interface in a standby state. When you removed the backup interface you allow the dialer interface to come into normal mode. Is there anything that would attempt to send traffic over the dialer interface (CDP, routing protocol, NTP, SNMP, other management protocols).

And failing all else, debug dialer would be an excellent place to understand what is bringing up the dialer interface.

HTH

Rick

bradlesliect Tue, 01/30/2007 - 22:52

Ok .... I think it could be interesting traffic being generated and being sent down my ISDN backup.

I have an access list applied to dialer-list1 which tells it to look for anything related to ospf,icmp,tcp,udp.

Could one of these be activating it? The minute I shut the dialer all matches on the access-list also stopped.

Could I configure dialer watch to check what it is? Is this easy to configure and would it break anything?

Richard Burts Wed, 01/31/2007 - 04:05

Brad

I do not think that configuring dialer watch will be very helpful in determining what is bringing up the ISDN. I suggest that the place to start is debug dialer.

HTH

Rick

Richard Burts Wed, 01/31/2007 - 07:50

Brad

Give it a try and let us know the results.

I generally check on the forum at some point during the day - depends on what is going on with my schedule.

HTH

Rick

bradlesliect Wed, 01/31/2007 - 12:36

Rick,

See below. The 192 IP Address is configured on dialer 3. The 224.0.0.5 address is not in the router's routing table. Why would it want to connect to that range?

123616: Jan 31 22:26:40.717 SAST: Se1/1:15 DDR: Dialing cause ip (s=192.168.225.21, d=224.0.0.5)

123617: Jan 31 22:26:40.717 SAST: Se1/1:15 DDR: Attempting to dial

123622: Jan 31 22:26:42.553 SAST: %LINK-3-UPDOWN: Interface Serial1/1:30, changed state to up

123623: Jan 31 22:26:42.553 SAST: Se1/1:30: interface must be fifo queue, force fifo

123624: Jan 31 22:26:42.561 SAST: %DIALER-6-BIND: Interface Se1/1:30 bound to profile Di3

123625: Jan 31 22:26:42.561 SAST: %ISDN-6-CONNECT: Interface Serial1/1:30 is now connected to N/A

123631: Jan 31 22:26:50.717 SAST: Se1/1:15 DDR: rotor dialout [best] least recent failure is also most recent failure

123632: Jan 31 22:26:50.717 SAST: Se1/1:15 DDR: rotor dialout [best] also has most recent failure

123633: Jan 31 22:26:50.717 SAST: Se1/1:15 DDR: rotor dialout [best]

123634: Jan 31 22:26:50.717 SAST: Se1/1:15 DDR: Dialing cause ip (s=192.168.225.21, d=224.0.0.5)

123635: Jan 31 22:26:50.717 SAST: Se1/1:15 DDR: Attempting to dial

123636: Jan 31 22:26:52.317 SAST: Di7 DDR: Cannot place call, no dialer string set

123637: Jan 31 22:26:52.317 SAST: Di9 DDR: Cannot place call, no dialer string set

123638: Jan 31 22:26:52.317 SAST: Di5 DDR: Cannot place call, no dialer string set

123639: Jan 31 22:26:52.317 SAST: Di6 DDR: Cannot place call, no dialer string set

123640: Jan 31 22:26:52.493 SAST: %LINK-3-UPDOWN: Interface Serial1/1:30, changed state to up

123641: Jan 31 22:26:52.493 SAST: Se1/1:30: interface must be fifo queue, force fifo

123642: Jan 31 22:26:52.501 SAST: %DIALER-6-BIND: Interface Se1/1:30 bound to profile Di3

123643: Jan 31 22:26:52.501 SAST: %ISDN-6-CONNECT: Interface Serial1/1:30 is now connected to N/A

123644: Jan 31 22:26:53.557 SAST: %ISDN-6-DISCONNECT: Interface Serial1/1:30 disconnected from , call lasted 1 seconds

123645: Jan 31 22:26:53.609 SAST: %LINK-3-UPDOWN: Interface Serial1/1:30, changed state to down

123646: Jan 31 22:26:53.613 SAST: Se1/1:15 DDR: has total 0 call(s), dial_out 0, dial_in 0

123647: Jan 31 22:26:53.613 SAST: %DIALER-6-UNBIND: Interface Se1/1:30 unbound from profile Di3

123648: Jan 31 22:26:53.621 SAST: Di8 DDR: Cannot place call, no dialer string set

123649: Jan 31 22:27:00.717 SAST: Se1/1:15 DDR: rotor dialout [best] least recent failure is also most recent failure

123650: Jan 31 22:27:00.717 SAST: Se1/1:15 DDR: rotor dialout [best] also has most recent failure

123651: Jan 31 22:27:00.717 SAST: Se1/1:15 DDR: rotor dialout [best]

123652: Jan 31 22:27:00.717 SAST: Se1/1:15 DDR: Dialing cause ip (s=192.168.225.21, d=224.0.0.5)

123653: Jan 31 22:27:00.717 SAST: Se1/1:15 DDR: Attempting to dial

123654: Jan 31 22:27:02.317 SAST: Di7 DDR: Cannot place call, no dialer string set

123655: Jan 31 22:27:02.317 SAST: Di9 DDR: Cannot place call, no dialer string set

123656: Jan 31 22:27:02.317 SAST: Di5 DDR: Cannot place call, no dialer string set

123657: Jan 31 22:27:02.317 SAST: Di6 DDR: Cannot place call, no dialer string set

123658: Jan 31 22:27:02.873 SAST: %LINK-3-UPDOWN: Interface Serial1/1:30, changed state to up

123659: Jan 31 22:27:02.873 SAST: Se1/1:30: interface must be fifo queue, force fifo

123660: Jan 31 22:27:02.881 SAST: %DIALER-6-BIND: Interface Se1/1:30 bound to profile Di3

123661: Jan 31 22:27:02.881 SAST: %ISDN-6-CONNECT: Interface Serial1/1:30 is now connected to N/A

cr1.ctn.nha.co.za#

123662: Jan 31 22:27:03.625 SAST: Di8 DDR: Cannot place call, no dialer string set

123663: Jan 31 22:27:03.937 SAST: %ISDN-6-DISCONNECT: Interface Serial1/1:30 disconnected from , call lasted 1 seconds

bradlesliect Wed, 01/31/2007 - 12:45

Below from Cisco site:

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

Serial 0: Attempting to dial xxxxxxxxxx

This message indicates that a packet has been received that passes the dial-on-demand access lists. That packet causes phone number xxxxxxxxxx to be dialed.

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

I have dialer-list 1 protocol ip list 130 configured and the access list looks as follows:

access-list 130 deny eigrp any any

access-list 130 permit ospf any any

access-list 130 permit icmp any any

access-list 130 permit tcp any any

access-list 130 permit udp any any

dialer-list 1 protocol ip list 130

.....so what's activating it?

Richard Burts Wed, 01/31/2007 - 13:14

Brad

I had not seen this when I posted my reply based on the debug dialer output that you posted. At the risk of repeating myself: what is causing it is OSPF. The 225.0.0.5 destination address is an OSPF multicast address.

If you do not want OSPF to trigger dialing activity you have a couple of options: you can change the network statements in OSPF so that the dialer interface does not match, you can change the dialer list so that OSPF is not interesting, or you can configure the dialer as an OSPF demand circuit.

HTH

Rick

Richard Burts Wed, 01/31/2007 - 12:56

Brad

The debug output is quite helpful. the 225.0.0.5 address is OSPF routing protocol traffic. Apparently there is an OSPF network statement which matches the IP address on the interface. And the dialer list which identifies interesting traffic is permitting OSPF.

So it is OSPF that is bringing it up and attempting to dial. If you do not want OSPF to bring it up then you could change the OSPF network statements so that they no longer match the interface address, you could change the dialer list to not make OSPF interesting, or you could configure the ISDN as an OSPF demand circuit.

HTH

Rick

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