ARC not working remotely: MultipleNatFound (ref#J9002M)

Hi! What’s not quite right with Roon?

· Can’t reach my Server, remotes or ARC

Can’t connect to my Server, remotes or ARC

· Other ARC issues

Tell us what's going on

· I want to connect to Roon ARC from outside my Wi-Fi network.
Roon ARC works fine on my home network, but it fails when I try to connect remotely; it cannot open the Roon Server port.

I have a Netgear router and a Synology NAS.

I opened the following ports on my router:
ROON ARC 55000-55100 55000-55100 192.168.1.29

Nothing works!

Here is the error I'm getting:

{
"ipv4_connectivity": {"status":"NetworkError","status_code":504,"error":"error code: 504
"},
"external_ip": {"actual_external_ip":"37.ccc.bbb.ddd","actual_external_ipv6":"null","router_external_ip":"172.aaa.aaa.bbb"},
"status": "status": MultipleNatFound
,
"natpmp_autoconfig": {"server_ip":"192.168.1.1","found_natpmp":true},
"upnp_autoconfig": {"server_ip":"192.168.1.1","found_upnp":true},
"multinat_autoconfig": {"status":"Failed","error":"Unknown Error code"}
}

Finally, I spoke with my service provider in Switzerland, and they confirmed that Bridge Mode is not an option on their router.

We tried using the DMZ to point the router, but that didn't work either!

Looking forward to hearing from you.

Tell us about your home network

· I want to connect to Roon ARC from outside my Wi-Fi network.
Roon ARC works fine on my home network, but it fails when I try to connect remotely; it cannot open the Roon Server port.

I have a Netgear router and a Synology NAS.

Please don’t do that and turn it off again. It exposes your whole machine to the whole internet without protection

From:

The problem is this in the error message (and DMZ doesn’t help with that anyway):

MultipleNatFound

Roon Support will be with you

Hi @Jacques_Simonnet,

Thank you for your post.

First off, it’s imperative that you re-enable the router’s firewall and not expose any of your devices by placing them in the DMZ. This is your home network’s basic line of defense against intrusion from the broader internet, and you don’t need to disable it for ARC to work.

The error message you’ve shared shows that Roon Server has detected a second layer of network address translation (NAT) beyond the expected layer imposed by your router. Put simply, this means that either a second router in your home network (or your internet service provider) is scrambling port forwarding above the level of Roon.

Do you have a second router in this setup? If not, then who is your internet service provider? You can usually reach out to them directly to inquire if a dedicated external address is available for port forwarding.

An alternative is to install Tailscale on your Roon Server machine and on your phone. This third-party VPN securely handles all the NAT traversal so you don’t even have to tinker with port forwarding.

There’s a lot of jargon and terminology floating around, so we’re here to assist. Please reach out with any questions and we’ll watch for your reply. Thank you!

Hi @Jacques_Simonnet,

Wanted to follow up on this, and we’re still watching for your reply. Were you able to re-enable the router firewall and check whether a second router or your ISP is introducing the extra NAT layer we mentioned? If you’d rather avoid port forwarding altogether, we can also help with the ARC and Tailscale option we sent over. Let us know what you find, and we can go from there.

Please note, if we don’t hear back from you this thread may close automatically soon. If the thread auto-closes and you need further assistance, please submit a reopen support request via the technical support help form below and specify that the issue should be reopened. Thank you.