Monday, December 14, 2015

How to connect an AT&T Velocity WiFi Hotspot as a LAN router

BLUF: turn off static IPas.

The AT&T Velocity WiFi hot spot can indeed function as a router for up to eight devices on a given subnet (e.g., 192.168.7.0/24). Devices shall be recognized and connected for normal LAN and WAN operations, but only if connected to the Subnet through DHCP. Static IP addresses are not supported and shall not connect.

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I recently bought a contract for the AT&T Velocity WiFi Hotspot:

     https://www.att.com/devices/zte/velocity.html

Very sweet.

My intent is to move from a landline ISP to the AT&T wireless provider since I'm changing my lifestyle to something considerably more mobile than the present.

It sets up two subnets: Main and Guest. You can set up different permissions for each and it supports up to eight users on Main and two on Guest.

I presently wirelessly entertain two laptops, a cellphone, a tablet, a printer, and an audio player (Logitech Squeezebox) (six devices) all connected to my (192.168.5.1) LAN. It has Internet connectivity through a Belkin N+ router connected with CAT 5 cable to a Motorola modem, connected in turn with coax to the local cable Internet provider.

They all sing and dance together. I can send audio streams from the Logitech Media Server - LMS installed on the laptop to the audio player (Squeezebox), print streams to the printer, sync the cellphone calendar with the OwnCloud server on the laptop, download the London Times to the tablet and more.

All cool.

But my current measly 300 MB AT&T cellphone account costs ~$90 a month. The cable service, offers 250 GB data a month, of which I only use around 20 GB — I don't watch television or play games. Just browsing, email, remote server administration, and system upgrade and software downloads, So I don't need no steenking 250 GB.

And the steenking cable bill is ~$60 a month.

So I'm paying $150 a month for a lot of what I don't want or need (too much landline throughput) and too little of what I do want (mobile wireless throughput).

Hence the change: I can cancel the landline and get 20 GB of AT&T wireless throughput for about the same amount as the previous combination.

But only one catch: how to connect the printer, audio, sync, etc?

Much googling, much experimentation. No Joy.

I could connect the cellphone, tablet, and laptop to the hot spot, but not the printer or audio device. They connect to 192.168.7.0/24 with no complaint on their part, but the hot spot does not see them.

Much googling again:

• Get a wireless Ethernet bridge. Put it in line to receive WiFi from the hot spot (192.168.7.1) and bridge it to the Ethernet port on the router. This would give me 192.168.5.0/24 subnet to the hotspot. Then connect my devices as usual to the router at 192.168.5.1 and it would all be fine.

     Sorry, the hot spot doesn't recognize the bridge either.

• Get smart about nmap, route -n, ip route add, and a host of other very geeky route table manipulation tools. I can now play the route tables like a keyboard. At least we figured out how to simultaneously connect Ethernet and WiFi (it's the "metrics", stupit...) but still no joy.

Hours spent. Interesting and informative hours, but a total waste of time insofar as solving the problem, except perhaps useful in eliminating many possible causes.

So time is a-wasting, let's just push the car back up the hill to see if the brakes fail again... :-(

Go back and set a static IP for the laptop on the hot spot network. Default gateway (the hot spot) is 192.168.7.1. So let's set the laptop to 192.168.7.2. Just like we did on the existing LAN: the default gateway (router) was 192.168.x.1, the network controller laptop was 192.168.x.2.

So change x=5 to x=7 and it should work the same, right?

Wrong.

Sigh, okay just stop thinking, just do the default: DHCP.

Poof! All of a sudden the laptop now connects. The hot spot does not support static IP addresses!!!

Woohoo! Finally!

Sure enough:

• Set the printer wireless configuration to "Automatic" (DHCP) and read its IPa: 192.168.7.66. We have to go through reconfiguring yast2 printer (we're on Linux openSUSE 13.2 but the principles are the same for other OSs). And then it just works.

• Next the Squeezebox. Same same, change from static IPa to DHCP and it just works. Read its IPa: 192.168.7.44.

• And the same for the CALDAV sync from Android to laptop. Enter the laptop's DHCP IPa (192.168.7.71) and poof! it works.

So:

The AT&T Velocity WiFi hot spot can indeed function as a router for up to eight devices on a given subnet (e.g., 19.2.168.7.0/24). Devices shall be recognized and connected for normal LAN and WAN operations in the order directed by their metrics, but only if connected to the Subnet through DHCP. Static IP addresses are not supported and shall not connect.

Now I can get on to more important things..

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