Unable to make inbound calls problem

I’m new to FreePBX/Asterisk need some help…
I am going to setup Freepbx system in our office. Everything is fine. We can make calls to outside world and do call transfer internally. But when we try to call extensions in the office from outside, calls keep dropping after only 1 second. I have contacted our voip provider and trunk settings has been checked. It should be OK.

The below is sip debug output when we make calls from outside.


Your firewall/nat is setup wrong

Retransmitting #4 (NAT) to

start with



Thank you for your help.

I already have done NAT settings in Freepbx and my router’s firewall settings. I do port forwarding just as the link said.

When I make calls from outside, I always got message from CLI without enable sip debug.

[2015-08-14 12:33:27] WARNING[5114][C-0000000f]: app_dial.c:2437 dial_exec_full: Unable to create channel of type ‘SIP’ (cause 20 - Subscriber absent)


Hi, is one of PC address running softphone Zoiper. The pbx server ip is


Then look to your router configuration. you can’t talk to an unregistered endpoint (subscriber absent)


I have tested internal extensions. All extensions are working and registered. I listed sip show peers below

localhost*CLI> sip show peers
Name/username Host Dyn Forcerport Comedia ACL Port Status Description
0xxxxxxxxx/04xxxx xx.xx.xx.xx Yes Yes 5060 Unmonitored
04xxxx (Unspecified) D Yes Yes A 0 UNKNOWN
801/801 D Yes Yes A 50xxx OK (3 ms)
802/802 D Yes Yes A 50xxx OK (3 ms)
803/803 D Yes Yes A 47xxx OK (41 ms)
free call/04xxxx xx.xx.xx.xx No No 5060 OK (50 ms)
6 sip peers [Monitored: 4 online, 1 offline Unmonitored: 1 online, 0 offline]



Yet the external calls are not getting through, that is a problem with your router.

There’s a space there. Don’t do that. You should also be speaking to the provider for support.


Thank you so much for your help. You are absolutely right. I try to use same freepbx settings on another server in a different location. It is working well without dropping calls issue.


When I check call history for one extension, I found a very weird call history.

Date CID Duration
08/15/15 10:55:46am “100” <100> sec

I am sure that I do no have extension 100 in my system. Why I get a call from CID 100 ?