controller cannot see minimServer

[simoncn]

(16-08-2012 03:19)psme Wrote:  So I rebooted the Win7 PC. Start minimServer again, and all is fine. Desktop Kinsky on the same PC always find minimServer. iPad via wi-fi also always find minimServer. Btw, on this PC with both minimServer and Kinsky controller, the PC is always using a fixed static IP (192.168.1.xxx). iPad on wi-fi is using DHCP via the router.

And I have a Qnap 212 with minimServer 0.52. The minimServer on the Qnap has exactly the same problem. Desktop Kinsky and iPad Kinsky (and other controller program/app) could not see the Qnap minimServer unless I let the controller wait a LONG time. Or I need to do a "restart" via minimWatch.

Since a reboot of the PC brought back the PC minimServer. I thought I need to reboot the NAS as well (the NAS is on DHCP, though I see that it always get the same IP). But before I reboot the NAS, I went to Qnap web admin->QPKG package, "Disable" minimServer, then "Enable" minimServer. Now, the Qnap minimServer is visible all the time! I don't need to reboot the NAS itself!

So, my guess is, it looks like the problem is on minimServer itself! And it seems this "disappear" problem only occur after minimServer is running for a long time, maybe several days or more, and with multiple "restart" operation as I'm adding albums to the library almost everyday.

Maybe... after a while, something is "stuck" in minimServer, or it's ohNet stack, and cause minimServer fail to subscribe the multi-cast group, hence minimServer does not see UPnP discovery message anymore. Though it can still send multi-cast message directly to the multi-cast address when it emit "alive" message...

Next time when minimServer act up, I will totally quit it, then re-run it...

There is no code in MinimServer or ohNet to subscribe to a multicast group. This is handled at lower levels in the TCP/UDP OS stack.

All these symptoms point to a network problem. It sounds like an issue with IGMP snooping in your router or switch. The router or switch sends out IGMP query commands and looks for responses. If the QNAP or PC fails to respond to these queries (for whatever reason), the router or switch removes it from the multicast group and never sends it any more multicast messages.

I have set up my switch to permanently add certain ports to the SSDP multicast group so they are excluded from IGMP snooping and possible removal from the SSDP group. If you can do this for the router or switch ports to which your NAS and PC are connected, I would recommend doing that. Alternatively, you could disable IGMP snooping in your router or switch configuration (probably a simpler solution).