Can you ping me now?

brian_d_foy on 2004-05-01T21:12:39

I'm in the Detroit Beer Company, watching the Red Wings on the big screen TV, waiting for my Thai Chicken pizza, and using their free wireless internet.

Their router set-up in novel: The router is 172.16.0.1, and the network is 255.255.0.0. I imagine someone else must be handling this for them, but still, why would a dinky restaurant, where I am the only computer in the place (everyone is watching hockey!), need so many addresses?

I think the supplier is NTN, which is what it says on these power-line insulator looking wireless access points.

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172.16/16 is reserved for private use

jmm on 2004-05-03T15:40:00

172.16/16 is one of the 3 ranges that are reserved for private use - so there must be a gateway on their network that is running NAT to translate the private internal addresses for any activity that connects to outside machines. Since these addresses are not visible to the outside world, there is no urgent need to restrict their network to a small size. While they could use a /24 network range, that just means that if they got sufficiently successful and had more then 254 customers at once, they would need to reconfigure. (In fact, the provider might have more than just the one location on this same network range and you wouldn't know unless you probed around carefully.)

Re:172.16/16 is reserved for private use

brian_d_foy on 2004-05-04T18:52:55

I figured that might be the case, although I have not run into that address space before. All this is covered in RFC 1918. Thanks for reminding me to read the docs. :)

I figure that they do have the same network for several places, since the fire marshall would probably be upset if 254 people were in the place.