SOLVED! preparing a Linksys 942 for external extension

[jsadan]

Question: I am trying to get a Linksys SPA942 registered as an external extension. What settings on the phone do I need to change? appreciate any help. Will update tomorrow

Answer:
Step 1: Make sure your firewall settings on your system/router are open.

My settings for my router:
Firewall:
SPI (Stateful Packet Inspection) - Disabled

Port forwarding: (Found these ports in 3CX wiki)
SIP TCP/5060-5060 -> Local IP of 3CX machine
SIP TCP/5090-5090 -> Local IP of 3CX machine
SIP UDP/5060-5060 -> Local IP of 3CX machine
RTP UDP/9000-9049 -> Local IP of 3CX machine

Step 2: The SPAXXX phone
From a factory reset (DHCP enabled) these are the changes I made.

SIP Tab:
SIP Parameters:
SIP TCP Port Max: 5090 (changed from 5080)

RTP Parameters:
RTP Packet Size: 0.020 (Was recommended in 3CX video)
Symmetric RTP: Yes (This was the setting that made this a living nightmare for me)

NAT Support Parameters:
STUN Enable: Yes
STUN Server: stun.3cx.com

Ext 1 Tab:
NAT Settings:
NAT Mapping Enable: Yes
NAT keep Alive Enable: Yes

Proxy and Registration:
Proxy: 99.14.10.xxx (Public IP of 3CX machine)
Register Expires: 300

Subscriber Information:
Display Name: External Extension
User ID: 19
Password: (password setup for this extension)

Special Thanks!
To:

KerryG - Thank you for your reply, this isn't the first post you've helped me with.

leejor - Thanks for having the patience and helping me step by step in this process. You are very active on the forums and I am sure we all appreciate your time and knowledge!

 

[leejor]

Re: preparing a Linksys 942 for external extension

RTP Port Min: 9000 RTP Port Max: 9003

You might try setting the number a bit higher, 9050. I think 3CX uses two for watch call but I'm not sure it they all start at 9000 and work up. Could a firewall/router be blocking packets?

 

[jsadan]

Re: preparing a Linksys 942 for external extension

Dont think so. I see the RTP packets in wireshark but it says it doesnt go through. I allowed RTP ports tcp/udp 9000-50000 and sip tcp/udp ports 5000-10000

Im not sure why the middle address is blank in the last error.

Now I see in the logs a ACK not received error

Wireshark code

Source:192.168.10.202 Destination: 99.145.242.5 Protocol: SIP Info: Status: 407 Proxy Authentication Required (0 bindings)

The PBX machine is asking for authentication to the phone. I am not sure why since it shows up as registered

 

[jsadan]

Symmetric RTP wasnt set to yes in the RTP Parameters... that was all

Edited the first post with Answer and Special thanks

 

[Discovery Technology]

For an external handset I would always use the outbound proxy setting and enable PBX delivers audio for the extension as well - this works much better for two-way audio on remote handsets, whether they're Linksys, Cisco, Yealing or Snom...

If you ever experiencing a one-way audio issue this is one of the most likely suspects...