Hardcoding ip address for arc

arc is not reaching my core from outside even though the core says all set and reachable.

i believe this is because i have two internet connection in the system, i don’t know which the core is using to go out to wan but i have opened a port to the core on only one system… can i specify in arc which ip to use to connect?

anyone know? thx

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I was wondering the same thing about our server.

We have a dual-Ethernet CORE server running on Ubuntu 20.04. One port (network A) is basically for client access. The other port (network B) is mainly for operations and maintenance. Both have internet access but I only have access to the router on network B for configuration so I’d like to specify which interface is used for ARC even if I have to manually edit a configuration file.

I have not tried ARC yet but will shortly and will report back on what I find.

Not possible. I’ve asked for these kinds of settings to be exposed.

Even if you could “force” ARC to one discovered IP I think that’d be nice.

Do you know on what basis the Ethernet port (IP address) is selected for use in ARC?

The server binds to all interfaces according to Roon. I do not know how ARC handles reachability tests from that point though. For all I know it tests everything and tells client about all addresses.

So is it possible to have clients on both interfaces accessing Roon Server that in turn publish their respective WAN addresses for use by ARC? (I forget what the initial setup is like. I’ll have to go over it again and see if the Server can appear on different networks for different clients.)

you should be able to specify which ip address you are activating port forwarding on. log into your routers firewall setting to specify this.

no, we need to know which ip address arc is hitting, which right now we have no access to see let alone specify.

i would like to hardcode it. or at least set an ip range and mask or something so i can keep arc from trying to tunnel through the wrong network. i think that core is just sending out over whichever network it currently sees, likely the highest order service network, but that’s not necessarily the network i need it to use.

any @roon with any advice here? didn’t file a support ticket as i’m sure you’re swamped with real fires to put out. thx

I asked this in a support thread but no answer yet. I’m going to have to set-up a lab so I can capture some packets off my phone <-sigh/->.

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nothin huh? not even a little hint?

lol. roon you are a special company, i will say that.

They are off for the weekend. It’s a small company.

For those with multiple network interfaces on Linux Cores the command

route -n

might be a help. It displays available network interfaces with their associated metrics (the lowest value is preferred).

For example:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface         UG    100    0        0 eno2         UG    101    0        0 eno1     U     1000   0        0 eno2     U     0      0        0 docker0   U     101    0        0 eno1   U     100    0        0 eno2

Here Ethernet 2 has the lowest metric and is the preferred route.

As of Ubuntu 18.04 netplan might be your ticket. Also note that ifmetric (sudo apt-get install ifmetric) can be used to change the metric of an interface in order to direct traffic as desired.

update: changed nothing but the app did seem to sort itself. the first time it took a while but it has managed to connect from wan and working well. so. it’s resilient. fyi. ymmv.

I’ve tried this and it worked for awhile but then it stopped working when I needed it the most :).
I am using Ubiquiti gear and was able to ssh into the router, run a tcpdump on the WAN interface, found the IP that the ARC was sending packets to and set that IP into the port forwaring rule. But they’ve changed the IP (maybe they have a load balancer/CDNs or something and it changes quite frequently).
I do agree that it would be nice to at least have a range of IPs.

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yeah. same. worked, then… not.

would be good to know the methodology here so we can adjust and make it play nice with everything.

pls. anyone who knows. thx