Problems with Cisco DPQ3212 Cable Modem and NAT

[David Demland]

Does anyone know much about a Cisco DPQ3212 Cable Modem? Cox put it in a few
months ago and I did not think much about it since every was working on my
network. However recently I had to log onto a VPN for a customer and I could
not. I started doing some checking and here is what I have found:

 

Doing a traceroute from my PC shows the following:

  1    <1 ms    <1 ms    <1 ms  881WRouter.42.168.192.in-addr.arpa
[192.168.42.254]

  2     8 ms     8 ms     7 ms  10.32.4.1

  3     7 ms     7 ms     7 ms  172.21.1.224

  4    18 ms    19 ms    29 ms  70.169.74.52

  5    21 ms    21 ms    22 ms  langbprj02-ae14.0.rd.la.cox.net [68.1.0.151]

  6    20 ms    21 ms    21 ms  72.14.215.221

  7    20 ms    21 ms    21 ms  209.85.248.185

  8   111 ms    32 ms    22 ms  209.85.142.91

  9    21 ms    21 ms    21 ms  lax02s21-in-f4.1e100.net [216.58.216.4]

 

Trace complete.

 

Doing a traceroute from the router show:

 

DemlandRouter#traceroute 216.58.216.4

Type escape sequence to abort.

Tracing the route to 216.58.216.4

VRF info: (vrf in name/id, vrf out name/id)

  1 10.32.4.1 12 msec 8 msec 8 msec

  2 172.21.1.224 8 msec 8 msec 8 msec

  3 70.169.74.52 32 msec 24 msec 32 msec

  4 68.1.1.19 20 msec

    68.1.5.139 20 msec 20 msec

  5 72.14.215.221 24 msec 24 msec 20 msec

  6 209.85.248.185 24 msec 24 msec 24 msec

  7 209.85.142.91 24 msec 20 msec 24 msec

  8 216.58.216.4 24 msec 20 msec 24 msec

 

The router's routing table looks like:

 

DemlandRouter#show route

route-map COX_NAT, permit, sequence 10

  Match clauses:

    ip address (access-lists): 110

    interface FastEthernet4

  Set clauses:

  Policy routing matches: 0 packets, 0 bytes

DemlandRouter#show ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2

       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area, * - candidate default, U - per-user static
route

       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

       + - replicated route, % - next hop override

 

Gateway of last resort is 98.165.177.1 to network 0.0.0.0

 

S*    0.0.0.0/0 [1/0] via 98.165.177.1

      10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks

C        10.0.42.0/24 is directly connected, Vlan20

L        10.0.42.254/32 is directly connected, Vlan20

C        10.42.0.0/24 is directly connected, Vlan1

L        10.42.0.1/32 is directly connected, Vlan1

      98.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

C        98.165.177.0/24 is directly connected, FastEthernet4

L        98.165.177.11/32 is directly connected, FastEthernet4

      172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks

C        172.16.42.0/24 is directly connected, Vlan30

L        172.16.42.254/32 is directly connected, Vlan30

      172.19.0.0/32 is subnetted, 1 subnets

S        172.19.73.61 [254/0] via 98.165.177.1, FastEthernet4

      192.168.42.0/24 is variably subnetted, 2 subnets, 2 masks

C        192.168.42.0/24 is directly connected, Vlan10

L        192.168.42.254/32 is directly connected, Vlan10

 

The modem's IP is 192.168.100.1, seems rather standard, and I can http to
the modem but all I get a status screen when I login. There is no username
and password to get to the status screen; but the I cannot find an
administrator login for the modem.

 

Looking at all the output it seems clear that the modem is doing a NAT,  of
private IP space 10.32.4.1, which would be a problem. I need to turn off the
NAT so that everything works. That is the issue, I can find nothing on line
about this and I have talk to Cox level two support and they have no idea.

 

The think that confuses me most is that I am getting a valid public IP on my
Router (I can even VPN in into my home network), but the traceroute never
shows my packets going through the public IP. Does any know how to login
into this modem and turn off NAT?

 

Thank You,

 

David

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