We are setting up an internal program, on an internal server that uses the private 172.30.x.x subnet... when we ping the address 172.30.138.2, it routes across the internet:

C:\>tracert 172.30.138.2
Tracing route to 172.30.138.2 over a maximum of 30 hops

  1     6 ms     1 ms     1 ms  xxxx.xxxxxxxxxxxxxxx.org [192.168.28.1]
  2     *        *        *     Request timed out.
  3    12 ms    13 ms     9 ms  xxxxxxxxxxx.xxxxxx.xx.xxx.xxxxxxx.net [68.85.xx.xx]
  4    15 ms    11 ms    55 ms  te-7-3-ar01.salisbury.md.bad.comcast.net [68.87.xx.xx]
  5    13 ms    14 ms    18 ms  xe-11-0-3-0-ar04.capitolhghts.md.bad.comcast.net [68.85.xx.xx]
  6    19 ms    18 ms    14 ms  te-1-0-0-4-cr01.denver.co.ibone.comcast.net [68.86.xx.xx]
  7    28 ms    30 ms    30 ms  pos-4-12-0-0-cr01.atlanta.ga.ibone.comcast.net [68.86.xx.xx]
  8    30 ms    43 ms    30 ms  68.86.xx.xx
  9    30 ms    29 ms    31 ms  172.30.138.2

Trace complete.

This has a number of us confused. If we had a VPN setup, it wouldn't show up as being routed across the internet. If it hit an internet server, Private IP's (such as 192.168) shouldn't get routed.

What would let a private IP address get routed across servers? would the fact that it's all comcast mean that they have their routers setup wrong?