On Sun, Sep 03, 2017 at 10:41:39AM -0500, Jon Schewe wrote: > My router is a Linux PC. It is connected directly to the cable modem. So I > know which addresses the router has: > >ip addr show > 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group > defaul > t qlen 1 > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 > inet 127.0.0.1/8 scope host lo > valid_lft forever preferred_lft forever > inet6 ::1/128 scope host > > valid_lft forever preferred_lft forever > 2: enp1s10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast > state UP > group default qlen 1000 > link/ether 00:d0:b7:3f:3f:d7 brd ff:ff:ff:ff:ff:ff > inet 73.37.165.179/23 brd 255.255.255.255 scope global enp1s10 > valid_lft forever preferred_lft forever > inet6 2001:558:6014:3e:a038:4872:4d66:a81/128 scope global > valid_lft forever preferred_lft forever > inet6 fe80::2d0:b7ff:fe3f:3fd7/64 scope link > valid_lft forever preferred_lft forever You have you default route pointing to 73.37.165.179. That is part of the 73.37.165.179/23 subnet. So 73.37.165.179 is what is replying to your traceroute. That gateway probably has 96.120.48.69 on one if its other interfaces, the interface which connects towards Comcasts core network. It is allowed to use any of its global scope IP addresses to send back the reply to your traceroute. Andrew