I've recently resolved a strange symptom on a 2600 configured for DSL, PPoE, and PAT. I'm still getting up to speed on Cisco, and I know this is a "duh" on my part, but in hindsight I'm curious why we observed the particular symptom we did. My understanding of ATM is vague here, as well as DDR as it applies to ATM / DSL.
The problem was that Dialer1 did not have a dialer-group entry, and correspondingly there was no dialer-list set up. DDR didn't occur to me immediately because I'm accustomed to seeing DDR on circuit-switched links (ISDN), not packet/cell-switched lines. (Why do you need interesting traffic for a line that's always on?)
With the absence of dialer-group and dialer-list, we'd observe hosts that could ping any destination *once*, followed by timeouts. The 2600 itself could ping all day long, and any hosts configured for NAT instead of PAT. So here's where I'm also confused - why is one ICMP packet getting through? Is the call coming up and immediately being torn down? (And not in a timing sense, but in an actual layer 3 sense?)
Or is there something more that I'm yet still missing?
Thanks for feedback!
! Edited for relevancy, anonymity. ! version 12.2 hostname foo ! vpdn enable ! vpdn-group pppoe request-dialin protocol pppoe ! voice call carrier capacity active ! mta receive maximum-recipients 0 ! interface ATM0/0 no ip address no atm ilmi-keepalive dsl operating-mode auto no fair-queue hold-queue 224 in ! interface ATM0/0.1 point-to-point pvc 0/35 pppoe-client dial-pool-number 1 ! interface FastEthernet0/0 ip address 10.0.0.1 255.255.255.0 ip nat inside ip tcp adjust-mss 1452 duplex auto speed auto ! interface Dialer1 ip address negotiated ip mtu 1492 ip nat outside encapsulation ppp dialer pool 1 dialer-group 1 ppp authentication pap callin ppp pap sent-username foo password 0 bar ! ip nat inside source list 1 interface Dialer1 overload ip classless ip route 0.0.0.0 0.0.0.0 Dialer1 no ip http server ! access-list 1 permit any dialer-list 1 protocol ip permit ! call rsvp-sync ! no mgcp timer receive-rtcp ! mgcp profile default ! dial-peer cor custom ! end