dhcp option 66

[steve-sydney]

In the event that option 66 has been setup on the router by the ISP and we cannot disable or remove it.
Is it possible to disable dhcp option 66 on the handset without disabling dhcp entirely?

Yealink t5 series. Would turning this setting off only turn off option 66?

Y

 

[JohnS_3CX]

According to Yealink documentation yes it will only prevent Option 66.

But you know what can be added on the ISP router? Your very own router with a private subnet, unaffected by the ISP DHCP options in case you run out of options

 

[steve-sydney]

I hear what your saying and appreciate that option.Technically that would have solved all the problems I've had plus the ones I'm anticipating can arise on that site.
I had problems with double NAT 15 years ago and have avoided it since. Maybe its time to revisit old beliefs.
Have you had good outcomes with this architecture?

 

[JohnS_3CX]

I had problems with double NAT 15 years ago and have avoided it since.

Guessing the NAT was between the PBX and phones in that case rather than above them.

So long as your PBX (or SBC) is on the same LAN as the phones and they can reach it without traversing NAT, then you aren't in a double NAT scenario.