T41s phone will not ping 3CX server

[ozydave]

Strange issue

 

3cx hosted in house.

 

Yealink T41s phones.

 

I have a port on the wall configured to the same VLAN as the 3CX server. This VLAN is dishing out IP’s via DHCP.

Majority of T41s get an IP address I can see them in the 3CX server and they all auto provision as they should. So they is no issue with the DHCP.

Now the strange bit.

I have some phones that get IP addresses on the correct VLAN, I can see them in the DHCP address leases.

I refresh the ‘phones’ tab on 3CX server and the phone is highlighted in bold. The MAC of the phone is assigned to and extension.

Its will not auto provision.

I can ping the phone from other devices on my network.

So now I go to the PhonesUI and login and start checking things. On the phoneUI network tab I go to diagnostics and try the ping. I can ping the gateway IP, I can ping other phones on the VLAN I can ping 8.8.8.8

But I cannot ping the 3cx server, I get 100% packet loss.

 

On a couple of the phones that will not auto provision I have given it a static IP address (on the same 3CX server VLAN) and it worked. But it will not work for all the phones.

 

I have made sure they are all on the correct VLAN. They all have the correct and same Firmware.

3CX version 16.0.9

Phone firmware 66.86.0.5

 

Any pointers??

 

Cheers

 

EDIT - the firewall on the 3cx windows server is switched off

Edited June 21, 2021 by ozydave
Update

[stevec_]

We've had issues in the past where 3CX had added the IP of the phone to the blacklist (Security > IP Blacklist), which prevents the handset from auto-provisioning.

[ozydave]

Cheers, Just double checked, nope nothing in there :-(

[Chris_Cook]

Is this a new or old setup?

 

First option I would try is to factory reset the handset by holding down the 'Ok' button, then following the prompt on screen. We had a couple of phones that went funny when they had done a recent update.

 

Another thing that's worked for me when I've had similar issues is to delete and re-add the extension on 3cx. Obviously, make a note of all the settings for the extension.

 

There might also be some settings in 3cx to configure vlans on the handsets themselves.

 

I'd also check if you have any dhcp options that depend on the mac address in order to configure the phone. It might be that one batch of handsets has a different OUI in the mac address.

[ozydave]

Thanks Chris,

Its a new setup. Been at it for days.

I have factory rest the phone, checked the IP blacklist. There is nothing funky on the DHCP scope.

 

I have taken the config off a working phone and applied it to the non working phone - no difference.

This morning i shut the 3cx server down, then put my laptop on the phone VLAN with the 3CX IP address (10,0,0,3). Connected the T41 up which gets an IP from the DCHP (10.0.0.20). Then from the phone UI | network diagnostics I can ping 10.0.0.3

So I know the are no problems with VLAN / DHCP scope.

So with phone still pluged in i shut the laptop off, powered up the 3CX server. From the phone cannot ping the 3CX server 10.0.0.3

 

I have double / triple checked the firewall is off on the server. I even stopped all the 3CX services - still no joy. From the server i cannot ping the phone on IP 10.0.0.20

 

[mdrabble]

Have you tried moving to the phone to a know working phone socket to check if it will work from there and vice versa - taking a know working phone to the socket with the issue?

 

Do you have any ACL configured on the VLAN port or check the VLAN config against other Phone VLAN ports?

[djm968]

Check DNS?

[ozydave]

Have you tried moving to the phone to a know working phone socket to check if it will work from there and vice versa - taking a know working phone to the socket with the issue?

 

Do you have any ACL configured on the VLAN port or check the VLAN config against other Phone VLAN ports?

 

Hi,

Nope there are no ACL's. I have moved the non working phone to a known working port. still the same issue.

 

- - - Updated - - -

 

Check DNS?

 

I'm only trying to ping via IP address

[ozydave]

I have just deleted the nick card out of the 3CX server and re added it out of curiosity. Still the same.

 

Just tried to give this phone a static IP address 10.0.0.50 the server and the phone could not ping each other

tried the static IP addresses 10.0.0.51, 10.0.0.52, 10.0.0.53 and the phone and server CAN ping each other and it auto provisions.

 

Gave it the static IP address 10.0.0.54, the server and the phone could NOT ping each other.

[djm968]

Is the phones firmware the same as the working phones and compatible with 3CX service pack?

[Chris_Cook]

have you got the sub-netmask set correctly on your 3cx server and DHCP scope?

 

I'm running that firmware on my desk phone and it works.

[ozydave]

defo subnet masks are correct. If i put laptops on the ranges they have no problems, pinging anything.

 

Other phones do have any problems at all.

[mdrabble]

Faulty phone??

[ozydave]

Faulty phone??

 

Was thinking that but if I put the phone on a different vlan with DHCP it will auto provision

[bald_pig]

Duplicate IP or a static route for that IP?