Private IP Address Connected to Dialer0

[Matt Wilson]

Could someone please explain what I am seeing here:

R1941#sh ip route              
!
Gateway of last resort is 0.0.0.0 to network 0.0.0.0
!
S*    0.0.0.0/0 is directly connected, Dialer0
      1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        1.9.4.0/24 is directly connected, Loopback0
L        1.9.4.1/32 is directly connected, Loopback0
      10.0.0.0/8 is variably subnetted, 7 subnets, 2 masks
C        10.1.1.0/24 is directly connected, Vlan10
L        10.1.1.1/32 is directly connected, Vlan10
C        10.1.4.0/24 is directly connected, Vlan40
L        10.1.4.5/32 is directly connected, Vlan40
C        10.1.6.0/24 is directly connected, GigabitEthernet0/0
L        10.1.6.5/32 is directly connected, GigabitEthernet0/0
C        10.20.23.126/32 is directly connected, Dialer0
      106.0.0.0/32 is subnetted, 1 subnets
C        106.69.xxx.xxx is directly connected, Dialer0
R1941#

The bit I'm concerned about is what is 10.20.23.126/32 doing in the routing table connected to Dialer0? I cannot ping it but a traceroute gives:

R1941#traceroute 10.20.23.123  
Type escape sequence to abort.
Tracing the route to 10.20.23.123
VRF info: (vrf in name/id, vrf out name/id)
  1 10.20.23.126 12 msec 12 msec 16 msec
  2 10.20.23.126 !A  *  * 
!
R1941#ping 10.20.23.126        
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.20.23.126, timeout is 2 seconds:
.U...
Success rate is 0 percent (0/5)
R1941#

What has this got to do with VRF?

Matt.

[Meheretab Mengistu]

Hello Matt,

On PPPoE, the peers IP addresses do not have to be in the same subnet. One guess I have, without looking at your configuration, is that R1941 learned its neighbor route, which you can disable using no peer neighbor-route interface level command.

HTH,

Meheretab

[Matt Wilson]

Hi  Meheretab,

Thanks for the reply. That might be it. It is strange that an ISP would use a private IP address on their external interface. So you're saying the next hop address is 10.20.23.126? It is a PPPoE connection to my ISP. I cannot ping it though. Is there anyway I can verify this?

Matt.

[Meheretab Mengistu · Accepted solution]

You can disable using no peer neighbor-route interface level command under interface dialer0.

HTH,

Meheretab

[Matt Wilson]

Thanks for your help.

[Meheretab Mengistu]

You are very welcome, Matt!