Dual-WAN and multicast

  • I'm not sure if this qualifies as a bug or it's expected behavior, but it took me forever to figure out what was going on…

    I have two WAN interfaces but I'm not using load balancing.  I have firewall rules set up to direct traffic from specific internal hosts to one or the other WAN interface (i.e. source destination * gateway WAN2).  When I do this, the miniupnpd service is no longer able to receive multicast SSDP requests from that host.  If I change the rule to (destination ! then miniupnpd starts seeing the multicast packets again.

  • That's expected behavior, it's doing exactly what you told it to do because it matches that rule, which tells it to forward to which ever gateway.

  • OK thanks.. It just seems a little strange that services running on the firewall will still "see" broadcast traffic (DHCP, etc) with the rule in place, but not multicast.  I would have thought it should always see both regardless of where they're being forwarded.  In any case, I ended up adding a rule "source * destination gateway *" at the top of the list which resolved the issue for all of the devices on the network.

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