coturn: Need help configurating my server correctly

2
votes

I am trying to set up a STUN/TURN server on my local computer for a webrtc application of me. I decided to use coturn. Note that my server is running behind a NAT.

So i fired up my Ubuntu VM and installed it. After reading through the wiki I got it working, atleast on my local network. For testing purposes, i use this site. Therefore, when i try it there with 192.168.178.25:3478, it works. When i try it with "public-ip":3478, it doesnt.

This told me, it is working locally and it should be a port/NAT issue. What i did:

1) I set the VM to Bridging

2) I opened the port 3478 on my router. To test if this is really working, i used telnet on a remote machine and it worked. Another test was that i set up a quick apache server on my local machine on port 3478 and it could be accessed from the outside. This told me that there is, or should be, not port/NAT issue and my turn server should be working.

Any ideas?

I am running my server with the following command:

"sudo turnserver -X "public-ip" -listening-port=3478 -v

The turnserver.conf looks something like this:

  • fingerprint

  • realm="myRealm"

  • lt-cred-mech

  • user=test:test

As telnet and apache server are both working, i am pretty sure i have a configuration issue. I basically spent the weekend trying and im really lost on what could be wrong.

Thanks for any help!

1
webrtcvoipstunturncoturn

1 Answers

3
votes

From the documentation of turnserver

-X, --external-ip <public-ip>[/private-ip] TURN Server public/private address mapping, if the server is behind NAT. In that situation, if a -X is used in form "-X " then that ip will be reported as relay IP address of all allocations. This scenario works only in a simple case when one single relay address is to be used, and no CHANGE_REQUEST STUN functionality is required. That single relay address must be mapped by NAT to the 'external' IP. The "external-ip" value, if not empty, is returned in XOR-RELAYED-ADDRESS field. For that 'external' IP, NAT must forward ports directly (relayed port 12345 must be always mapped to the same 'external' port 12345). In more complex case when more than one IP address is involved, that option must be used several times, each entry must have form "-X ", to map all involved addresses. CHANGE_REQUEST NAT discovery STUN functionality will work correctly, if the addresses are mapped properly, even when the TURN server itself is behind A NAT. By default, this value is empty, and no address mapping is used.

So, it is not enough that you expose only the listening port from the inside LAN to the public network but all ports that you are going to use to relay. Please, note what is said in the same documentation:

--min-port <port> Lower bound of the UDP port range for relay endpoints allocation. Default value is 49152, according to RFC 5766.
--max-port <port> Upper bound of the UDP port range for relay endpoints allocation. Default value is 65535, according to RFC 5766.

You should choose a range of ports in the server, configure with them the options --min-port and --max-port and create a NAT rule to expose those ports to the public side of the router without change.