This is a followup to several prior threads:
Link1
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Summary: In firmware 8.5, there is a bug when using Outbound Policy + VLANs, which manifests as devices being unable to connect to each other and/or to get DNS. Reverting to 8.4.1 seems to fix the issue (however, read below, as it seems 8.4.x also has the bug):
This seems primarily to affect devices using an ethernet port set to VLAN Access, when the VLAN is also set to use Outbound Policy specific to one WAN.
New information: After giving up on firmware 8.5, I went back to firmware 8.4.1 (on my Balance One). Although this seemed to immediately fix the issues, after a few days, I’m seeing the problems again!
The pattern is interesting:
- Firmware 8.5: the bug manifests every few hours, and lasts for about an hour, then magically clears up
- Firmware 8.4.1: the bug manifests every few days, and lasts for several hours.
My conclusion is that firmware 8.4.1 also suffers from the same issue, but it doesn’t happen as regularly. Something in the firmware 8.5 version is triggering the bug more quickly.
What is going on?
I have done at least one packet capture showing the specific bug: an IOT device on my VLAN is trying to do DNS lookups, and being told that Port 53 is not available. See Packet capture
The symptom of the bug coming and going randomly, makes me wonder if there is a service on the Peplink router which is getting stuck (which triggers the bug), then eventually the service crashes and is restarted (which clears up the bug). What service? Is this a NAT service? DNS? Firewall? Unclear.
In any case, since I can now convincingly demonstrate the issue both in firmware 8.4.1 and 8.5, I’m going to go back to firmware 8.5 and see if I can isolate the problem further. I’ll report back when I know more.