I have a customer with an AT&T Uverse 2Wire592 router to which I installed a CCTV DVR a couple of years ago.
They called me yesterday because they couldn't see the cameras remotely.
I tried login remotely to the DVR and couldn't do it neither through the app or a browser.
I asked them to do a check port for port 80 and 6036 using the Open Port Check Tool at canyouseeme.org and both test came back as an error.
I'm only assuming that AT&T has done some sort of changes to the router or block some IPs since they still have internet access, and this setup has been working for a couple of years without a single hiccup.
Have you guys seen this happening before?

In a related note I have a customer with AT&T also, but in this case I have a Mikrotik router on the DMZ (DMZ Plus Mode) of the AT&T router. The Tik is getting the WAN IP not from the AT&T router's pool, but from the AT&T directly (sort of bridge mode). In this case the issue I'm having is that every couple of days the connection slows down, and rebooting the AT&T router fix the issue for a couple of days.
The customer setup and appointment with AT&T last week and wanted me to be present to check the issues. I got there ahead of the AT&T to make sure that everything on my end was OK, but the guy never showed up.
Long story short I was able to speak on the phone with the guy that was assigned to this call, and he told me that if the system was working properly there was nothing that he could do. That if the system was acting up at the moment that he were there he would replace the router, but that he only carried refurbished units.
After a few minutes talking to the guy we became "friends", and the guy confessed to me that AT&T doesn't allow them to do any changes on the router, not even the SSID or the encryption key to the WiFi.
According to him (take this with a grain of salt), the firmware on those units is designed in a way that will slow down the connection if any of the defaults parameters are changed; which defeats the fact of having those parameters built in in first place.
Then I realized han besides putting the Mikrotik router on the DMZ I had disable the WiFi on the router, so I enabled it back and I haven't heard about this issues again from that customer.

So what other issues are you guys experiencing with AT&T that I should be aware of?