Here is a working Workaround for routed VPNs / Radio in other subnet / OpenVPN TUN Setup

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  • Updated 3 years ago
For the network experts in the forums, that need a workaround for the broadcast based discovery (e.g. complex network topo or OpenVPN TUN etc...) I've got a working workaround now. It simply cost's you one or two raspberry pi devices...


The manual, source & binary download is on Github: https://github.com/krippendorf/flex6k-discovery-util/blob/master/README.md

It's provided without any support. It's my hobby, not my job :) Good network knowledge is required, otherwise waiting for a WAN enabled SmartSDR would be recommended. Contributions very welcome! There are no security features included, so you should know, what is going on in the network when relaying the discovery broadcast outside the radio's subnet.

Here is how that looks like with openVPN and TUN via LTE connection: 




With SmartSDR 2.0 - I hope - it will work out of the box and I can delete my workaround.


73
HB9FXQ
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Frank, HB9FXQ

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Posted 3 years ago

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Hardy

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Hello, Frank,

I have made this up to now quite easy without programming.
On a Linux system in local net:

sudo socat UDP4-RECVFROM:4992,fork UDP4-SENDTO:MY_REMOTE_IP:4992

Replace MY_REMOTE_IP with the remote SSDR.

73, Hardy
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Frank, HB9FXQ

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Sounds good


Can you run DAX & CAT at the same time? Simple is better, that's sure. I verified it with Ncat from terminal.


Socat should work also, but I guess, you'd need it on both sides of the tunnel, since PKGs must be broadcasted to 255.255.255.255 that SmartSDR AND Dax AND Cat discover the radio fine.


Can you share a bit more details about your network subnets?


73, HB9FXQ Frank
(Edited)
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Hardy

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Hi Frank,

>Can you run DAX & CAT at the same time?
As far I see ... not at the same destination pc.
Only one application at a windows pc.
I do use this only for my maestro.

73, Hardy
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Frank, HB9FXQ

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that's the difference, therefore re-broadcast it to 255.255.255.255 will allow any client / app in the local network to discover the radio. But for a single Maestro with static DHCP lease / static IP your simple socat is the most simple solution :)

73, Frank
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Frank, HB9FXQ

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A lightweight, router CPU friendly, GO based version of the workaround is "work in progress". Needs some testing, cleanup & a bit documentation. It is already working on my lab / PfSense routers: https://github.com/krippendorf/flex6k-discovery-util-go/blob/master/src/github.com/krippendorf/flex6... 

Contributions welcome :) 
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Frank, HB9FXQ

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Now in test on PfSense: https://github.com/krippendorf/flex6k-discovery-util-go CPU at ~1%