Yealink phones to do not reconnect randomly after loss of internet

[su27]

We have been having issues with Yealink phones, primarily T41P, not reconnecting to 3CX in event of connectivity loss i.e. internet router rebooted or ISP issue.

Initially we started with 3CX hosted through a 3CX partner, it was v14. We then purchased our own 3CX v15 PRO 8 calls and host it in Azure cloud. So we changed the hosting company, changed the 3CX version but the problem remains. We have an SSL Certificate and the CA is on the Yealink approved list. Phones run the latest firmware 36.80.0.130 and have been reprovisioned and reset a few times. The problem does not affect all phones and every time. There is no pattern on one occasion 2 out of 12 phones pop out, another day it could be a different phone etc. I have to reboot phones to connect to the network again.

I suspect this is not 3CX problem but Yealink but I thought I would check if someone else had it

 

[YiannisH_3CX]

How are the phones provisioned?
Are you using as SBC or are the phones provisioned with remote STUN?

 

[su27]

phones are deployed using remote STUN

 

[carolinainnovative]

Having the same issue with T46Gs using remote stun.

 

[dig1234]

What type of router are the phones behind. I saw this issue when we were testing remote STUN and suspected that it's related to the phones not using random source ports.

Ended up scrapping the remote stun idea after much effort because of too many little issues. A properly configured VPN has worked better for us.

 

[su27]

we are using PepLink Balance Once http://www.peplink.com/products/balance-one/

VPN is an interesting thought. do you use Yealink Openvpn? I will give this a try

 

[dig1234]

We are using IPSec on the router. (sonicwall, not my choice) So long as you QOS voice over the other traffic any vpn should work. It just takes careful configuration and testing to make sure you really are prioritizing the RTP. We do this over regular high speed internet and it works. If the phones are not roaming (eg going home with employees) I would think it would be easier to maintain a router based vpn than Openvpn to the handsets. Even though it is a cool feature in concept.