Routing of broadcast traffic



  • Is it possible in pfSense to route broadcast traffic on one subnet to another?  For instance, I want traffic destined for the broadcast address of subnet 192.168.0.0/24 to be forwarded to the broadcast address of subnet 192.168.1.0/24, and vice versa.  (LAN and OPT1).  So for broadcasts on one subnet should span to the other as well.  But I do NOT want to bridge them. Is this possible?



  • What are you trying to achieve? What protocol(s) are involved?

    I doubt that it's possible with an out-of-the-box pfSense - you're probably going to need some kind of relaying service on pfSense.



  • UDP.  I want to play StarCraft on my LAN, which has two subnets.  It uses UDP broadcast traffic to port 6111 on 255.255.255.255 so obviously currently only the subnet the server is on sees its traffic, and only the subnet the other pc is on sees the polling broadcasts from that pc.  Both the server and client(s) send out UDP broadcasts, so the forwarding will have to happen both ways.

    I tried udp-proxy, and it sort of works.  I can see the game appear in the list, however the moment I click on it or wait 5 seconds it disappears again.



  • Try using VLan it should pass all broadcast traffic to each subnet. Or simply re-subnet your network like 192.168.0.0/23.



  • If I re-subnet my network how will I control the firewall rules between the two networks?  Surely then they become one subnet?  I want to keep the Wireless subnet separate from the LAN for security reasons.

    I'll have a look at VLAN's - thanks.



  • I am not that familiar with setting up VLANs.  How would I go about it?  I assume I want one VLAN since it defines the broadcast domain, right? But how do I join both my NIC's to this VLAN? Not sure I follow… Wiki/articles here did not help that much as most people uses VLANs with VLAN capable switches and/or the WAN interface.



  • VLANs will not work!
    VLANs are used to separate groups on the same layer1.
    They kind of do the exact opposite of what you want.

    What you need is some kind of broadcast proxy.
    This might help you:
    http://forum.pfsense.org/index.php/topic,15569.msg81508.html#msg81508



  • Thanks.  I ended up doing exactly that and it works perfectly.  I had to modify the guy's code a bit but here is what I did (if someone else has the same problem): http://www.waldonell.com/me/node/336



  • Thanks! This is very useful.


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