On Sun, Jan 31, 2010, Hetz Ben Hamo wrote about "weird traceroute": > Hi, > > I'm checking something very weird: I'm doing a traceroute to check > something, and then I see this: >.. > 7 ten3-1.brdr2.lnd.nv.net.il (212.143.14.134) 115.718 ms 116.122 ms > 117.610 ms > 8 10.80.1.1 (10.80.1.1) 143.145 ms 148.781 ms 153.709 ms > 9 ten4-0.lon.leaseweb.net (195.66.225.56) 113.546 ms 117.951 ms 118.661 > ms >... > See line 8. - 10.80.1.1?? I thought that 10.x.x.x wasn't suppose to > be routable outside internal LAN.. > > Am I missing something here?
The host 10.80.1.1 is probably some sort of private gateway that sits between Netvision's backbone (7) and the London Internet Exchange (9). Both 7 and 9 know how to contact this IP address, but it isn't routable from the general Internet. You got back a reply from him because *you* are routable so the reply could reach him. You managed to "find" this host because you (your traceroute) sent him a UDP datagram with a TTL of 8, causing the packet to stop at this stage of the route and be returned to you. -- Nadav Har'El | Sunday, Jan 31 2010, 17 Shevat 5770 n...@math.technion.ac.il |----------------------------------------- Phone +972-523-790466, ICQ 13349191 |An apple a day keeps the doctor away. An http://nadav.harel.org.il |onion a day keeps everyone away! _______________________________________________ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
