<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head><body>Routers have multiple addresses, typically at least 3 if not more: one facing end users, one facing upstream and a loop back address. Some network operators choose to use a loop back address for traffic replies in things such as traceroutes.<div><br></div><div>Especially as some may be using rfc1918 addresses on some interfaces.</div><div><br></div><div><br></div><div style="font-size:100%;color:#000000"><!-- originalMessage --><div>-------- Original message --------</div><div>From: Jon Schewe <jpschewe@mtu.net> </div><div>Date: 9/3/17 7:47 AM (GMT-06:00) </div><div>To: TCLUG Mailing List <tclug-list@mn-linux.org> </div><div>Subject: [tclug-list] Odd networking on Comcast </div><div><br></div></div><div dir="ltr"><div>I'm trying to debug some issues with my internet connection. I have Comcast and the traceroute results are not coming back what I expect. On my router my routing table looks like this:</div><div><br></div><div><div>>netstat -rn</div><div>Kernel IP routing table</div><div>Destination Gateway Genmask Flags MSS Window irtt Iface</div><div>0.0.0.0 73.37.164.1 0.0.0.0 UG 0 0 0 enp1s10</div><div>73.37.164.0 0.0.0.0 255.255.254.0 U 0 0 0 enp1s10</div></div><div><br></div><div>Given that, I expect the first hop in a traceroute to be 73.37.164.1, but it's not.</div><div><div>>traceroute -n 8.8.8.8</div><div>traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets</div><div> 1 96.120.48.69 8.890 ms 14.915 ms 15.659 ms</div><div> 2 68.85.168.121 14.833 ms 15.604 ms 15.575 ms</div><div> 3 96.108.188.62 14.502 ms 14.484 ms 14.665 ms</div><div> 4 96.108.188.101 15.455 ms 16.596 ms 16.574 ms</div><div> 5 68.86.94.81 28.011 ms 26.859 ms 26.841 ms</div><div> 6 68.86.85.158 24.289 ms 19.757 ms 22.386 ms</div></div><div>...</div><div><br></div><div>Can anyone explain what's going on here?</div><div><br></div><div>- Jon</div><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><a href="http://mtu.net/~jpschewe" target="_blank">http://mtu.net/~jpschewe</a><br><br></div></div>
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