Public External IP, no STUN server needed

[Andy Schmidt]

Hi,

Under General Settings | STUN, the instructions say "TO DISABLE STUN RESOLUTION, DELETE STUN ENTRIES", which is what is recommended when 3CX is on a public IP addrss.

Consequently, I blanked out the 6 STUN fields.

Now my log is full with:
23:57:10.585 StunClient::loadStunList [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
23:57:00.523 StunClient::loadStunList [CM306002]: There is no valid STUN server specified! External IP can not be resolved.
etc (every 10 seconds).

How can I REALLY disable STUN, so that 3CX understands that it's not needed and thus does NOT need to "warn" me every 10 seconds that I turned something off that is supposed to be turned off?

 

[bblokey]

I believe you need to remove the server address and the time values as well...

 

[Andy Schmidt]

The STUN Server Options screen has 6 fields (includig the 2 ports fields). Of those one field is a timeout and the other is a repeat time. ALL fields have been emptied by me. The result is the error message every 10 secs.

 

[Andy Schmidt]

How does one disable STUN!?

Hi,

3CX seems to have general problems with configurations that don't want/require STUN?

I followed the instructions of "blanking" out the STUN fields in the General Settings, but clearly, 3CX does NOT honor that, but still tries to use the "empty" settings.

Here the log for VOIP outdial:

09:09:39.073 MediaServerReporting::STUN [MS101003] C:3.2: Possible firewall problem. Address mapping failed on STUN server xxx.xxx.xxx.130:3478 for local address ":9000"
09:09:38.980 CallCtrl:nSelectRouteReq [CM503004]: Call(3): Calling: VoIPline:10000@[Dev:sip:[email protected]:5060]

 

[Andy Schmidt]

Any idea, how to disable "STUN" so that it doesn't cause problems elsehwere in the system?

 

[SY]

Hi Andy,

STUN is used by PBX to discover the topology of network. It is the eyes of PBX. STUN is informational and isn't functional service. I cannot understand why do you try to force PBX to be blind?
Could you please specify any real reasons?

Thanks
P.S. Looks like "hints" are out of date (hopefully only sometimes)

 

[Andy Schmidt]

Dear Stepan:

Sorry - that's just my ignorance. VOIP is new technology to me, so I'm not well educated on these matters.

While setting up gateways, phones, 3CX etc. I had somewhere encountered information that lead me to believe that STUN was "optional" and only needed/used when NAT was translating internal IP addresses and ports to public IP addresses and ports. In fact, I thought I had read NOT to use STUN unless needed to avoid it causing problems. But I'll be first to admit that I could have misread/misunderstood.

Your technical manual, page 65, seems to imply that it is OPTIONAL and NOT needed:

"STUN Server Options
You can specify a STUN server to use for external IP address resolution. You can
optionally specify a custom port."

Your web site has an information about STUN servers that states:

"The STUN server allows clients to find out their public address, the type of NAT they are behind and the internet side port associated by the NAT with a particular local port."

Since I don't use NAT, it seemed natural to me not to mess things up with a service that tries to find out NAT information that doensn't exist.

Finally the "help" information in the General Options screen states

"These settings will be the defaults used for STUN resolution of the external IP Address...."

Since in my case we don't have to "resolve" the external IP address, it made sense to disable the settings as per the documentation to avoid possibly misinterpretation/overhead...

Best Regards,
Andy

 

[SY]

Dear Stepan:

Sorry - that's just my ignorance. VOIP is new technology to me, so I'm not well educated on these matters.

While setting up gateways, phones, 3CX etc. I had somewhere encountered information that lead me to believe that STUN was "optional" and only needed/used when NAT was translating internal IP addresses and ports to public IP addresses and ports. In fact, I thought I had read NOT to use STUN unless needed to avoid it causing problems. But I'll be first to admit that I could have misread/misunderstood.

Your technical manual, page 65, seems to imply that it is OPTIONAL and NOT needed:

"STUN Server Options
You can specify a STUN server to use for external IP address resolution. You can
optionally specify a custom port."

Your web site has an information about STUN servers that states:
"The STUN server allows clients to find out their public address, the type of NAT they are behind and the internet side port associated by the NAT with a particular local port."
Since I don't use NAT, it seemed natural to me not to mess things up with a service that tries to find out NAT information that doensn't exist.

Finally the "help" information in the General Options screen states "These settings will be the defaults used for STUN resolution of the external IP Address...." Since in my case we don't have to "resolve" the external IP address, it made sense to disable the settings as per the documentation to avoid possibly misinterpretation/overhead...

Best Regards,
Andy

Dear Andy,

I've provided you additional information. It is the "workaround" for issue related to technical manual. (bugs(mistakes) are not specific only for executable modules)

Thanks for verification of technical manual.
P.S. Please don't talk about "ignorance". I didn't mention it in my post.

 

[Andy Schmidt]

Hi Stepan:

I didn't mean to sound "upset". I truly AM ignorant (it's not YOU saying it, it's me admitting to it).

This technology is new to me so I read as much as I can. And, from my reading it simply seemed like wherever I looked in 3CX, STUN was "optional", in fact, there were even some manuals that sounded like it would be best to turn it off if no NAT was involved. I was simply trying to answer your question, why I would think that turning STUN off was the right thing to do for MY configuration.

Since 3CX's screen also said it's optional and that you can turn it off, I expected 3CX to work without glitches if STUN was off (because NAT is not used). So I felt is was a good idea for me to report when I noticed some odd behavior when I used the documented product feature to turn STUN off.

Again, I VERY much appreciate you taking the time and sharing your insight!

Best Regards,
Andy

 

[Andy Schmidt]

What happens of all 3CX customers when stun.3cx.com is down?

>> I cannot understand why do you try to force PBX to be blind?
Could you please specify any real reasons <<

Yes - my U.S. provider requires no STUN. I'm on a public IP, don't use NAT, so I don't need STUN. Right now, my likely point of failures are:

- The availability of my own connection
- The availability of my US VOIP provider, whom I chose based on reliability, backup power and other fail-safe mechanisms etc.

Now, if I'm forced to use someone's STUN server, it adds a THIRD party to that, meaning that my ability to place/receive phone calls is subject to one ADDITIONAL potential point of failure. Per example, let's assume stun.3cx.com sits in Guatemala and I know nothing about how it is hosted, what kind of power backup it has, what kind of redundant Internet pipes it has. I have nothing against that country, but I might not have chosen this particular location for my mission critical application!?

Do you now understand, why I prefer NOT to "poison" a two party relationship (my VOIP provider and I) by introducing an unnecessary THIRD party?

Let's face it, if stun.3cx.com was ever down - what happens to all those 3cx customers in the world who didn't even realize that their systems are volunerable to some incident half way around the world? I think it's rather critical that 3CX should fix the various parts of the system where STUN is required even though no NAT is taking place so that your customers have the option to turn it off completely!