Why privite IP show up?

[kcbell]

I have ATT broadband and using a Cisco 3101 router. Following is the traceroute of cisco.com inside the router. Why the 1st address is a 10.x.x.x address instead of 12.x.x.x address? My intranet address is 10.128.x.x range. Any idea, anyone?

Thanks

traceroute cisco.com
Translating "cisco.com"...domain server (204.127.198.4) [OK]

Type escape sequence to abort.
Tracing the route to cisco.com (198.133.219.25)

1 10.142.96.1 28 msec 40 msec 16 msec
2 12.244.84.65 20 msec 16 msec 36 msec
3 12.244.64.129 20 msec 12 msec 36 msec
4 12.244.72.42 28 msec 16 msec 36 msec
5 gbr1-p70.st6wa.ip.att.net (12.123.44.57) 44 msec 28 msec 32 msec
6 gbr3-p70.st6wa.ip.att.net (12.122.5.157) 16 msec 40 msec 28 msec
7 gbr4-p40.sffca.ip.att.net (12.122.2.197) 36 msec 48 msec 36 msec
8 gbr5-p70.sffca.ip.att.net (12.122.5.145) 44 msec 52 msec 60 msec
9 gar1-p360.sj2ca.ip.att.net (12.122.2.253) 36 msec 44 msec 36 msec
10 12.127.200.82 60 msec 36 msec 96 msec
11 sjce-dirty-gw1.cisco.com (128.107.239.53) 56 msec 40 msec 36 msec
12 sjck-sdf-ciod-gw1.cisco.com (128.107.239.98) 76 msec 40 msec 40 msec
13 cisco.com (198.133.219.25) 36 msec 72 msec *

 

[hexn]

I dont think I understand your post. Looks to me like ATT has put you on a 10.x network.

 

[kcbell]

inikis:

That is exactly what I think. The traceroute is a cut and paste. So it is real. Have any one seen this before?

 

[LoopyLoo]

The first address is your default gateway address (or a router defined in a static route on your PC). It is the internal address of the router. What subnet mask are you using? 255.0.0.0?

 

[kcbell]

LoopyLoo:

My default gateway is 10.128.128.10. That is the address of the E0 port. E1 is for Internet. This traceroute was done at the router NOT at the PC. Subnet mask is 255.255.255.0. One more thing is very interesting, the bootpc(67) port is being hit by the 10.142.96.1 address constantly. I am not home now. I will post the log tonight. Looks like someone's computer is doing it....how and why?

 

[LoopyLoo]

Looks like they have you on a 10 address. Do you have a block of static addresses or even one? It looks like they are natting you.

 

[kcbell]

I have a 12.x.x.x valid Internet IP address. It is dynamic.

 

[kcbell]

This is the log of the 10.142.96.1 address and denied by the router.
Feb 13 21:45:33.998: %SEC-6-IPACCESSLOGP: list 102 denied udp 10.142.96.1(67) ->
255.255.255.255(68), 8 packets

 

[benzito]

LoopyLoo has the answer. Your ISP is using rfc1918 addresses w/ NAT. Probably using a many to one configuration to route internet traffic.

 

[kcbell]

Brnzito: Why would ATT/Comcast be using 10.x ip with NAT? I understand how NAT works but I don't understand the reason behind the NATting. Please help!