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IP Helper on EdgeRouter

Submitted by -
Status: New Idea

Hi guys,


I need to forward udp broadcasts addressed to from one vlan into another. Ubnt support recommended to use mdns reflector/repeater or the external bcast functionality described in this link for this purpose. Unfortunately, both don't work to forward udp broadcasts to


Currently I am solving this via configuring an vlan ip routing interface in each of the vlans at EdgeSwitch, which supports the IP helper functionality (additionally to the EdgeRouter, which is the standard gateway in each of the vlans/subnets). By this way, normal unicast packets are routed via the standard gateway on EdgeRouter, but udp broadcasts are forwarded via the ip interface on EdgeSwitch. Additionally I have an ACL created on EdgeSwitch to allow only udp's to 3804 pass through the routing interface.


But because routing is a layer3 functionality and the EdgeRouter is the 'real' layer3 device instead of EdgeSwitch, it would be much nicer, if this ip helper functionality could also be implemented in EdgeRouter by the next release, not only at EdgeSwitch.


Because this functionality is already implemented in EdgeSwitch, it shouldn't be much developing work to also implement it in EdgeRouter and it's hopefully going to be available soon. Furthermore, it would be much nicer to be able to manage access between the two vlans/subnets by EdgeRouter's firewall, not via an ACL at EdgeSwitch.


Thanks a lot in advance!!

Hopefully it's going to be available soon.


Best regards,



on ‎05-30-2017 01:10 PM

Hi guys,


I just read about spoon25's great work to implement the external bcast-relay tool described here also for ER-X and ER-X SFP models, not just ERL etc. like it was implemented in the original tool.


Thanks to that I am now able to forward broadcasts via my ER, not just via my EdgeSwitch as described above.

As already asked by @spoon25 in post 13 of this topic, it would definitely be great if UBNT could implement this already nicely working feature into the native EdgeOS software as soon as possible!!


Just one thing, that would be needed to cleared, is about wether the bcast-relay is affected by firewall rulesets. At least with my configuration, it is not affected, as discussed here in post 14 and here in post 138.


Thanks a lot!!