dialer0 still up even though physical down

Unanswered Question
Jan 31st, 2007

i have a static default pointing out to dialer0, then a floating static pointing out another interfacce, however when the physical interface that the dialer interface is tied to goes down, the dialer interface stays up and the floating static never takes over, is there a way to track the status of the physical adsl interface instead of the dialer interface?

I have this problem too.
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mschooley Thu, 02/01/2007 - 12:53

i'm not quite sure this fits, my primary interface is dialer0 pppoatm, via an adsl connection, negotiatie ip address, by backup link is out fa0/0, both are up. i have static route pointing at dialer0 and a static route pointing at next hop out fa0/0 metric 10

also if traffic is sent out dialer0 want to nat using that interface, and if traffic is sent out int fa0/0 nat using that interface. the issue is that when I pull the adsl interface, the atm goes down yet dialer0 stays up therefore that floating static never takes over. with the above solution, i'm not sure what I would poll unless i did a traceroute and found out the next hop.

sundar.palaniappan Thu, 02/01/2007 - 13:44

What you can do is track a public domain IP, like yahoo.com/cisco.com, and add a static route for that polled host address to point to the dialer interface. The router would ARP for that address out pppoatm int and hopefuly, if proxy ARP is enabled on the ISP end their router should respond and you should be able to successfully track. If you can successfully track then anytime the polled address becomes unavailable the floating static route should kick in to route the traffic via the ethernet interface.



mschooley Thu, 02/01/2007 - 18:29

yes but once the public ip is available again thru the backup interface, since both are to internet, then other static should come back up, shouldn't it since device i'm tracking is suddenly available. I need a way to track atm0, i really don't understand why dialer0 doesn't go down with atm interface.

sundar.palaniappan Thu, 02/01/2007 - 19:50

Just block ICMP echo or whatever traffic type, you choose to use to track the polled IP, via the backup fastethernet interface using an outbound ACL.



steveo123 Sun, 02/04/2007 - 18:11

Dialer interfaces can be configured independently of any physical interface and applied dynamically as needed. make sure the same dialer pool-member are exsisting within the dialer int and ATM int.

Also are you using Cisco1721 with ADSL WIC ?

mschooley Mon, 02/05/2007 - 05:38

no, a 3725 with and adsl interface. Do you have an example of what you mean. In my situation dialer0 is primary so statics are

ip route inter dailer0 and

ip route x.x.x.x 10

but when you pull the cable on adsl, dialer0 stays up.

interface ATM0/0

no ip address

no atm ilmi-keepalive

dsl operating-mode itu-dmt

pvc 0 0/35

encapsulation aal5mux ppp dialer

dialer pool-member 1

interface Dialer0

ip address negotiated

ip access-group 101 in

ip nat outside

ip virtual-reassembly

encapsulation ppp

dialer pool 1

no cdp enable

ppp chap hostname XXXXX

ppp chap password XXXXXXX

ppp pap sent-username XX password XX


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