Traceroute Theory

I am toying with trace route, my application send a ICMP echo request with a ttl of 0 every time i receive a time exceeded message i increment the ttl by one and resent the package, but what happens is I have 2 routers on my network i can trace the route through these router but third hop always ends up being on开发者_如何转开发e of the open dns servers same ip every time no matter where i traceroute to. AFAIK this is the correct traceroute implementation, can anyone tell me what i am doing wrong?

It's possible that both routers connect to the same peer, and you'd get the described behaviour.

Without more info, it's not really possible to answer your question.

While it's hard to say without any additional information, the best bet would be to install some packet sniffer — probably wireshark / www.wireshark.org — and compare the icmp packets — what goes on the wire with your traceroute, and what does the system /usr/bin/traceroute (or \windows\system32\tracert) send.

If you have a NAT router on the path it can screw up your nicely adjusted TTL's