I was doing a traceroute to 208.67.222.222 (resolver1.opendns.com) to see if I can figure out the reason for the initial startup delay and observed the following curious thing (this is on a DSL line from Romtelecom marketed under the “ClickNet” brand here in Romania):
1 13 ms 13 ms 13 ms ... computer's public ip ... 2 14 ms 13 ms 13 ms 10... 3 55 ms 54 ms 54 ms 10... 4 54 ms 53 ms 54 ms 10... 5 53 ms 53 ms 53 ms 10... 6 53 ms 51 ms 51 ms Frankfurt.de.ALTER.NET [139.4.25.21] ...
I’m not a networking guy (although I do have some basic knowledge), so there probably is some very good technical reason for this network structure. I just found it curious how public traffic can be routed trough private address spaces and that this is visible from the outside. Live and learn.