After having the switch out of the mix for a week or so, as expected, it made no difference. OTN physically/directly attached to the pfSense and channels still went missing. I was hoping maybe somehow the switch was caching something in its internal routing or ARP table, but that doesn't seem to be the case.
That's odd. Channels stay available even when channels are switched? I would assume that if you switch to a different channel then the new channel is subscribed to and the old channel is unsubscribed (via IGMP). So either the unsubscribing does not happen or there is something else that your ISPs box does.
Yep, it seems as if the channels vanish after a while - not right away. I don't know exactly when they stop working, but initially they all seem to work fine switching through them.
I put the ISPs router back in (so pfSense out), and have a packet sniffer set up like a mouse trap with peanut butter trying to grab anything to/from what appears to be a management port, 4567. I'm hoping there is a clue, or a way to access that ISP device's internal configuration to see if I'm missing something in my multicast setup.
Can you just open the firewall completely temporarily? This could rule out that the firewall is causing the problems.
Thanks for the suggestion. I've put that on my list of things to try. I need to look at it again, but IIRC there are rules showing up in the pfSense logs that do not seem to be accessible in the UI that I've been able to find.
Each new configuration takes some amount of time (have been giving it a few days or so) for the channels to stop working, which is making this difficult to sort out.
I'm not sure if this is related but when I was looking at some packet traces a couple of weeks ago with the ISP's box in place, I think I noticed something that may be different about two of the channels I'm having trouble with - each of these trouble channels has the same source IP as at least one adjacent channel. I haven't gone through all channels recording their IP addresses, I just happened to notice when changing channels on these particular ones, the source IP wasn't changing (but the channel/programming changes just fine). On other channels that always work, they don't (from what I could see) have the same IP.
The two problem channels do not share a source IP address (one is channel 13 and the other channel 119) with each other, they just seem to share one with an adjacent channel (ie (don't remember exact specifics) channel 13 and 14, channel 118 and 119).