[cisco-nas] ping fails over dialer interface

Fri Sep 26 05:18:50 EDT 2008

Dinesh,

the cisco shouldn't arp for any address over the Dialer, it's a p2p
interface.  

Looking at the config: you have routing disabled! please enable this
("ip routing"), and please also enable CEF ("ip cef" globally and "ip
route-cache"/"ip route-cache cef" on all the interfaces..

	oli

Dinesh Bhonsle <> wrote on Friday, September 26, 2008 2:19 AM:

> Hi,
> 
> I have cisco850 - pppoe client,  i am unable to ping to the default
> gw on the bras. pc-----cisco850(CPE)-------netgearSwitch(pvid
> 4001)------BRAS 
> 
> cisco-850  gets a  ip address from BRAS  as 172.16.1.3.  multibind
> interface at BRAS is 172.16.1.254. so when i try to ping 172.16.1.254
> from cisco, encapsulation fails, may be arp res 
> 
> cpe1#sh run
> Building configuration...
> 
> Current configuration : 1540 bytes
> !
> version 12.4
> no service pad
> service timestamps debug datetime msec
> service timestamps log datetime msec
> no service password-encryption
> !
> hostname cpe1
> !
> boot-start-marker
> boot-end-marker
> !
> enable secret 5 $1$pb71$nc1Bi.IaAJLdMPXtXeggO0
> enable password test123
> !
> no aaa new-model
> !
> resource policy
> !
> ip subnet-zero
> no ip routing
> no ip dhcp use vrf connected
> !
> ip dhcp pool myownpool
>    import all
>    network 192.168.100.0 255.255.255.0
>    dns-server 68.2.16.25
>    lease 7
> !
> !
> no ip cef
> vpdn enable
> !
> !
> !
> !
> !
> !
> !
> !
> !
> interface FastEthernet0
> !
> interface FastEthernet1
>  shutdown
> !
> interface FastEthernet2
>  shutdown
> !
> interface FastEthernet3
>  shutdown
> !
> interface FastEthernet4
>  description "UPLINK connected to BRAS"
>  no ip address
>  ip virtual-reassembly
>  no ip route-cache
>  duplex auto
>  speed auto
>  pppoe enable group global
>  pppoe-client dial-pool-number 1
> !
> interface Vlan1
>  description "dhcp interface for home-users"
>  ip address 192.168.100.1 255.255.255.0
>  ip nat inside
>  ip virtual-reassembly
>  no ip route-cache
> !
> interface Dialer0
>  ip address negotiated
>  ip mtu 1492
>  ip nat outside
>  ip virtual-reassembly
>  encapsulation ppp
>  dialer pool 1
>  dialer-group 1
>  ppp chap hostname team at teambackbone
>  ppp chap password 0 team
> !
> ip classless
> ip route 0.0.0.0 0.0.0.0 Dialer0
> !
> no ip http server
> no ip http secure-server
> ip nat inside source list 1 interface Dialer0 overload
> !
> dialer-list 1 protocol ip permit
> !
> control-plane
> !
> !
> line con 0
>  no modem enable
> line aux 0
> line vty 0 4
>  password test
>  login
> !
> scheduler max-task-time 5000
> end
> 
> 
> cpe1#ping 172.16.1.254
> 
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 172.16.1.254, timeout is 2 seconds:
> 
> *Mar  1 06:55:26.082: IP: tableid=0, s=172.16.1.4 (local),
> d=172.16.1.254 (Dialer0), routed via RIB 
> *Mar  1 06:55:26.082: IP: s=172.16.1.4 (local), d=172.16.1.254
> (Dialer0), len 100, sending 03C2C9D0:                   45000064
> 004E0000          E..d.N.. 03C2C9E0: FF016028 AC100104 AC1001FE
> 080031FD  ..`(,...,..~..1} 03C2C9F0: 00130000 00000000 015E4ADC
> ABCDABCD  .........^J\+M+M 03C2CA00: ABCDABCD ABCDABCD ABCDABCD
> ABCDABCD  +M+M+M+M+M+M+M+M 03C2CA10: ABCDABCD ABCDABCD ABCDABCD
> ABCDABCD  +M+M+M+M+M+M+M+M 03C2CA20: ABCDABCD ABCDABCD ABCDABCD
> ABCDABCD  +M+M+M+M+M+M+M+M 
> 
> 
>   1 06:55:26.082: IP: s=172.16.1.4 (local), d=172.16.1.254 (Dialer0),
> len 100, sending 03C2C9D0:                   45000064 004E0000       
> E..d.N.. 03C2C9E0: FF016028 AC100104 AC1001FE 080031FD 
> ..`(,...,..~..1} 03C2C9F0: 00130000 00000000 015E4ADC ABCDABCD 
> .........^J\+M+M 03C2CA00: ABCDABCD ABCDABCD ABCDABCD ABCDABCD 
> +M+M+M+M+M+M+M+M 03C2CA10: ABCDABCD ABCDABCD ABCDABCD ABCDABCD 
> +M+M+M+M+M+M+M+M 03C2CA20: ABCDABCD ABCDABCD ABCDABCD ABCDABCD 
> +M+M+M+M+M+M+M+M 03C2CA30: ABCDABCD ABCDABCD ABCDABCD          
> +M+M+M+M+M+M 
> *Mar  1 06:55:26.086: IP ARP: creating incomplete entry for IP
> address: 172.16.1.254 interface Vlan1 
> *Mar  1 06:55:26.086: IP ARP: sent req src 192.168.100.1
>                  0018.1849.c9ee, dst 172.16.1.254 0000.0000.0000 Vlan1
> *Mar  1 06:55:26.086: IP ARP: sent req src 172.16.1.4 0018.1849.c9ee,
>                  dst 172.16.1.254 0000.0000.0000 Dialer0
> *Mar  1 06:55:27.086: IP ARP: sent req src 192.168.100.1
>                  0018.1849.c9ee, dst 172.16.1.254 0000.0000.0000 Vlan1
> *Mar  1 06:55:27.086: IP ARP: sent req src 172.16.1.4 0018.1849.c9ee,
>                  dst 172.16.1.254 0000.0000.0000 Dialer0.
> *Mar  1 06:55:28.086: IP ARP: sent req src 192.168.100.1
>                  0018.1849.c9ee, dst 172.16.1.254 0000.0000.0000 Vlan1
> *Mar  1 06:55:28.086: IP ARP: sent req src 172.16.1.4 0018.1849.c9ee,
>                  dst 172.16.1.254 0000.0000.0000 Dialer0
> *Mar  1 06:55:29.086: IP ARP: sent req src 192.168.100.1
>                  0018.1849.c9ee, dst 172.16.1.254 0000.0000.0000 Vlan1
> *Mar  1 06:55:29.086: IP ARP: sent req src 172.16.1.4 0018.1849.c9ee,
>                  dst 172.16.1.254 0000.0000.0000 Dialer0
> *Mar  1 06:55:29.086: IP: s=172.16.1.4 (local), d=172.16.1.254
> (Dialer0), len 100, encapsulation failed 03C2C9D0:                  
> 45000064 004E0000          E..d.N.. 03C2C9E0: FF016028 AC100104
> AC1001FE 080031FD  ..`(,...,..~..1} 03C2C9F0: 00130000 00000000
> 015E4ADC ABCDABCD  .........^J\+M+M 03C2CA00: ABCDABCD ABCDABCD
> ABCDABCD ABCDABCD  +M+M+M+M+M+M+M+M 03C2CA10: ABCDABCD ABCDABCD
> ABCDABCD ABCDABCD  +M+M+M+M+M+M+M+M 03C2CA20: ABCDABCD ABCDABCD
> ABCDABCD ABCDABCD  +M+M+M+M+M+M+M+M 