[ale] Why would a uverse ethernet work but not a switch?

[alan at alanlee.org]

I'm sure Uverse isn't providing multiple routable (real) IPv4 addresses. 
  So the router is likely NAT masquerading any downstream devices that 
try to initiate an outbound connection to the rest of the world.  In 
fact, it's very likely both your local router and an upstream network 
router are both NAT masquerading as there isn't any reason to have 
routable IPv4 addresses anywhere in AT&T customer infrastructure.

So my guess is AT&T pushed a firmware update to the router to change the 
masquerade policy.  Why?  Because they are AT&T of course.

If your SLA covers providing you with general Internet service via the 
wired router path, take it up with AT&T and have patience.  If they 
expect you to only get it via WiFi from the router, take it up with AT&T 
and prepare for failure.  Also if the later, you could turn a close 
proximity wifi client connection into bridge wired ethernet with a 
number of commodity devices.

You can do some poking around and report back.  Plug a PC into the 
switch and see if you get a DHCP lease from the router.  Report back the 
lease details if any.  And if you do get a lease, make sure you can ping 
the default route and perform a traceroute to a North Star such as 
8.8.8.8 and report back.

-Alan


On 2019-04-09 15:15, Derek Atkins via Ale wrote:
> Hi,
> 
> I'm temporarily living in an apartment while my house is being
> renovated, and we have AT&T Uverse here.  Uverse uses ethernet for the
> "remote" TV box, and until a week ago I had installed a switch to allow
> me to plug in both the uverse box and my smart tv (the wifi there is
> spotty).  See diagram:
> 
> [router] - [wall] - [building wiring] - [wall] - [switch] - TV and 
> Uverse
> 
> I was gone for a week and when I came back the switch was no longer
> syncing to the router, so neither the TV nor Uverse were working.  At
> first I thought it was the switch that went bad (there was a power
> outage when I was gone), so I ordered a replacement.  However, the
> replacement switch also does not work.  What is strange is that if I
> plug the uverse box in directly to the wall it works fine.  Moreover, 
> if
> I plug the switch directly into the router using a local patch cord it
> works there.  So the only time the switch fails is when it uses the
> building wiring.
> 
> As I said before, I'm in an apartment so don't really have access to 
> the
> building wiring.  I can ask the building management, but I suspect they
> will foist me off to AT&T.  And if I go to AT&T, I suspect they will 
> say
> they don't support switches -- and will ignore me because their Uverse
> box works just fine.
> 
> SO...  Any ideas where I go from here?  They are only using 4 wires (2
> pairs) for the in-wall wiring, but that should be fine even for my
> little netgear switch.  At least, it was until a week ago.  I don't
> understand why the Uverse box works but a switch wont.
> 
> Any ideas?
> 
> -derek