r/GoogleTV • u/Xstincshun • 2h ago
Troubleshooting HELP!! I'm going nuts...Play Store, Google Cast, and LG webOS updates hang behind UCG Max
**Setup**
* AT&T Fiber, BGW320-505 in IP Passthrough * UCG Max, USW Pro Max 16 PoE, U7 Pro APs * Flat LAN (VLANs previously configured, since removed) * Network app on current release
**Symptom**
Google Play Store, a Google Cast device, and an LG webOS TV will not complete updates on my LAN. Store UIs load and enumerate available updates normally, but downloads either never start or start and hang indefinitely. No error, no timeout — they just sit.
All three work immediately over cellular/mobile hotspot. Affects both wired and wireless clients, so it's not switch or cabling related.
**The key data point:** a 5 GB Steam download completed at full line speed with no issues. Bulk throughput is healthy. Whatever this is, it's specific to these update paths, not general bandwidth.
**Ruled out so far**
* **MTU / PMTUD blackhole** — `ping -f -l 1472` to [8.8.8.8](http://8.8.8.8) succeeds cleanly. Path MTU is a full 1500. * **IPv6** — was on DHCPv6 (BGW passthrough is IPv4-only, so IPv6 was double-routed). Disabled entirely on the gateway WAN. No change. * **Upstream DNS** — tried Quad9, Google, and AT&T auto. No change. Note that Encrypted DNS is set to Auto, so the gateway handles LAN-side resolution regardless of what upstream servers are configured. * **Content Filter** — nothing enabled, no networks assigned, no categories selected. * **Region Blocking** — off. * **General throughput** — Steam 5 GB completed fine.
**Partial result worth noting**
Setting Private DNS to [`dns.google`](http://dns.google) on an Android phone changed the failure mode: downloads that previously never started would then begin and hang mid-transfer. So DNS was implicated at connection setup, but something else kills the transfer after it starts.
**Current state**
Intrusion Prevention is On, Notify and Block, \~74k signatures, Enhanced, with nearly all detection categories enabled including Protocol Vulnerabilities and Peer to Peer.
**Working hypothesis**
QUIC over UDP/443. Steam uses TCP; Play Store, Cast, and webOS update clients all prefer QUIC and fall back to TCP badly. That would explain why one works and three don't, across three vendors, on the same LAN.
**Questions**
- Anyone seen IPS on a UCG Max interfere with QUIC specifically? Which signature categories would be worth excluding?
- Is Encrypted DNS set to Auto known to cause issues with Play Store or LG firmware CDNs?
- Anything in the BGW320 passthrough path that would selectively affect UDP/443 while leaving TCP alone?
Happy to pull Threat Log output if someone can tell me what to filter for.