I've tried searching for this but, it's difficult to come up with good search terms and I haven't found any useful results so, if this has been covered, please point me to a thread and accept my apologies in advance.
I've got a couple of AT&T accounts running on OpenWRT devices, one is a prepaid account on a MOFI 4500 and the other is an unlimited plan from a corporate account on a WE826 running Open Rooter. Both accounts are experiencing the same issue and it's beginning to drive me nuts.
The prepaid account has been running for a few years now on the same hardware with no recent configuration changes or firmware updates. Up until a few months ago, it was rock solid and just worked. Then out of nowhere, we started having issues where network clients could ping an address like 22.214.171.124 but, they wouldn't get any DNS resolution and not other traffic would pass. I tried disconnecting and reconnecting the modem but, the only solution to the problem would be to reboot the router. Sometimes after a reboot it would work for days, sometimes just a few hours, there really wasn't any rhyme or reason to it. Recently, in the last month, this issue has become much more frequent. I thought maybe I had hardware problems but, I don't anymore because...
We have another rural location that needed Internet setup so I got the second AT&T account and the WE826. It's using a Quectel EM25 (I have a Sierra MC7455 coming) and I just recently got it running. I'm running essentially the default configuration, all I did was set the password and the APN. With this one, when I start doing something more bandwidth intensive, like watching Amazon Prime or Netflix, I get about 30 minutes or so and then none of the clients can access the Internet. If I log into the router though, it can ping outside addresses, traceroute works fine and it's resolving names with no problem so it's just not passing inside traffic for some reason. Again, I can try to disconnect/reconnect the modem but, the only thing that gets it working again is a reboot.
So, I don't know if there is something I'm missing in OpenWRT that I can at least better troubleshoot what's going on or change to help prevent this. Both of these accounts are hotspot accounts but, I've got the TTL set to 65 anyway. I've tried setting up the connection monitoring on the WE826 to get it to reboot itself but, since it never loses connection itself, that doesn't work, it has to be rebooted manually. I'm at a loss as to what to try or where to look. I suspect AT&T is doing something to me, I don't know how to even verify that's the case so I can go to my reseller and complain to him to get him to fix it.
I welcome any help anyone can provide. It's extremely annoying to have to reboot the router 3 or 4 times to watch a single movie.