Issues accessing Slingbox in different subnet.

Posted on 2007-10-16
Last Modified: 2013-11-13
I have a network with two separate subnets. One for all the AV equipment in the house and one for all the computers. The computer network is in the subnet and the AV equipment is in the subnet.  The router is a "m0n0wall", with 3 interfaces. WAN, LAN and AV.

The issue that I am having is that I cannot access the Slingbox on the AV network from the LAN (computer) network. The m0n0wall has a firewall, however there are rules in place to allow all traffic of all types between the two subnets. I am able to ping across the subnets with no problem, however accessing resources such as the Slingbox from the LAN network does not work 100%. I am able to ping the Slingbox but unable to authenticate.

I suspect the issue is related to routing between subnets and possibly different types of packets used by the Slingbox.

Here's a diagram:

o WAN/ISP (Public IP Address)
o m0n0wall Router/Firewall
|\o LAN Subnet:  Computers (
 \o AV Subnet:  AV Equipment and Slingbox (

The two subnets are equal peers and are not nested within another subnet. Both have direct access to the WAN/ISP.

Any assistance would be greatly appreciated.
Question by:triphius
    LVL 3

    Accepted Solution

    If you're able to ping between the hosts then routing must be correct.

    If auth isn't working then is it a restriction in the slingbox admin that is preventing non-local (i.e. not the same as the local subnet) access?

    either than or it's possibly using broadcast packets in some way which by default won't be forwarded by your router (you get this for instance connecting to drive/printer shares).  If in doubt, use wireshark or something to look at the traffic on the AV network when a LAN client is trying to connect.  If you see say UDP broadcast packets, or multicast (or IGMP packets), then you may need to set up your router to forward these as well.

    Author Comment

    Thank you for the info.  I have been able to access network shares from the Music and DVD servers on the AV network from a PC on the LAN network.  However, I'm pretty sure that it's got to do with broadcast packets or something of the sort.  Unfortunately, the Slingbox website isn't very technical in it's support documents.

    Also, I'm not sure how you'd route broadcast packets....  Any help would be greatly appreciated.
    LVL 3

    Assisted Solution

    by:Adrien de Croy
    If you are able to install some packet capturing software on another machine on that subnet that is able to access the slingbox, you can use that to determine if broadcast packets are coming into play.

    We normally use CommView, but WireShark is also good (and is free).  It needs to be on a machine that will see the packets.  If you are using a switch on the AV LAN, then the capturing software would need to be installed on a machine that directly accesses the slingbox on that same AV LAN.

    Once you have determined whether broadcast is in play, you can decide where to go from there.  The slingbox tech support may also have an idea about using it from another subnet.

    Author Comment

    Thank you for the suggestions.  I'm sure that these will lead to a solution; and since I will be unable to try any of the suggestions until next week, I will go ahead and award AdriendeC the points.

    Thank you again.

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