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Bear with me a bit as I might be completely misunderstanding something. I'm a very-early-in-education networking student and at the moment I'm tinkering with my router settings while studying.

I noticed my provided by Comcast router has a setting listed for WAN default gateway. I had never heard of this before but I assumed that was essentially the router Comcast has set up to accept connections for all home routers in the area to send the connections deeper within their network, or something similar. To confirm this, I ran tracert 8.8.8.8 and expected to see the WAN default gateway's IP appear in the output, but it did not.

Now I'm simply curious, what is the WAN default gateway? And if I was correct about what it does, why wouldn't it appear in tracert's output?

802.11
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2 Answers2

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The WAN default gateway is simply the IP address of the next hop out of your router (to the Internet).

Tracert traditionally includes the egress IP address of the interface on the return path to the sender. So it's possible (likely even) that interface of the WAN default gateway router has multiple IP addresses, and the egress IP address is just not the same as what you have configured for the WAN default gateway.

If you tracert to the WAN default gateway IP address you have configured, it may resolve the the same name as the first hop you see on your tracert to 8.8.8.8.

Greg Askew
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  • One possible reason for why it behaves like that is that the configured gateway IP could be a virtual IP that at any given time can point to one of multiple routers and each router have a unicast address which they'll be using in replies to packets that haven't explicitly been targeted at the virtual IP. – kasperd Jan 22 '18 at 00:11
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The default WAN gateway from your router does appear on the tracert list - however, it is completely possible that it doesn't use the address of the interface that's facing your router.

A router has multiple interfaces and the ICMP Time exceeded message that is used for tracert list can originate from any of its addresses, very often its 'main' address, i.e. the address facing the ISP core.

If you tracert your router's WAN/default gateway you'll probably find it on the second hop.

Zac67
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