CP925

[maguirej]

We have been working an issue with a Yelaink CP925 phone where outbound dialing ocmplete, but it would not ring for inbound. After rebuilding the accounts, firmware, and pcaps we saw that it was not responding to the invitation. Registrations would work without issue.

We have been able to get it functioning by enabling tcp instead of udp on the device. Has anyone else had issues with this?

 

[JohnS_3CX]

Hello,

Please share the following information:

- PBX Version
- Are you using modified templates?
- What version is the CP925 firmrware
- What type of provisioning did you use? (STUN / LAN / SBC)

 

[my13]

Same issue. TCP resolves it for now.

 

[JohnS_3CX]

If you are over STUN consider installing a 3CX SBC: https://www.3cx.com/docs/3cx-tunnel-session-border-controller/

 

[rickybogo]

was this ever resolved, im having the same issues?

 

[JohnS_3CX]

was this ever resolved, im having the same issues?

Also over STUN?

 

[rickybogo]

Yes.

 

[JohnS_3CX]

Then as above, consider installing an SBC at your premises.

Otherwise, you will have to set a static IP on then phone, then port forward the SIP port and RTP range on the local firewall, and disable its SIP ALG service. Without this, the ports will not be accessible you will most likely face audio issues, and missed calls. Ensure that the ISP modem is also not running SIP-ALG.

An SBC of course can bypass all these limitations, and it is the recommended method of deploying remote phones.

 

[rickybogo]

I have no issues with Fanvil v64 phones, also onsite and using STUN.

 

[rickybogo]

I have no issues with Fanvil v64 phones, also onsite and using STUN.

i might try one of them as a router phone then.

 

[JohnS_3CX]

I have no issues with Fanvil v64 phones, also onsite and using STUN.

Hi Ricky,

We have other people who tell us the exact opposite: that their Yealink phones work perfectly on STUN, but not their Fanvils for example. That's because STUN is unpredictable - you currently rely on the firewall to maintain the correct ports and SIP sessions open automatically, and each firewall will behave differently unless you manually forward the ports to enforce them being open. It makes its own decisions and often we see the exact same issues you describe because it is not under the control of the admin or the PBX.

Hence we recommend against using STUN, and on StartUP and Hosted by 3CX it is entirely unsupported - the use of an SBC is mandatory there. So either get an SBC in place, or manage your ports manually if you prefer using STUN.

Keep in mind that we created the SBC exactly for this purpose - so people don't have to worry about these common STUN issues, and it can bypass NAT and SIP-ALG for you. It makes remote phones very reliable. We now also offer firmware on some models that include a built-in SBC so you don't need to use a standalone machine as an SBC and make remote phone deployment much easier and reliable.

You are lucky because you already have some phones that can act as a router phone
See all models here: https://www.3cx.com/sip-phones/

Why not make use of this awesome feature on your V64 phones? They support it and they can act as the SBC for your CP925 too! You can move away from STUN entirely using the V64 phones.

 

[JohnS_3CX]

i might try one of them as a router phone then.

Actually, you can reconfigure them all to be their own individual router phone if you want.

But don't forget - you have to factory reset them after setting them up in 3CX.

The phone will automatically provision after the reset if you are on V18 Update 7