King Computer Solutions

Archive for the VOIP Category


Asterisk audio inbound or outbound not working when iptables firewall enabled

Due to attempted hacks on VOIP boxes we need to increase security by allowing SIP access only from the relevant IPs using iptables firewall In the case below the Asterisk VOIP server is sitting behind a NAT firewall and has the relevant config set for this. I found upon enabling the linux firewall that while […]


Turn off using cellular mobile data and using VOIP when overseas to save money on an iPhone

We have had a few clients subsequent from coming back from overseas tell us about –


Call forward to mobile cell phone rings and can answer but has no sound on asterisk server

If running your asterisk server behind a firewall you may experience these symptoms: internal users can call mobile extensions configured with follow me and the call goes through and can be heard with no problem. If you have a rule configured so that external callers after a timeout calling internal extensions are then routed to […]


Voicemail not working and drops out after elastix asterisk backup and restore

After doing a backup of asterisk from one system, and restoring to a fresh build, you may find that when someone goes to voicemail, there is a seconds silence then it drops out. If you use *97 and try to record a message, it immediately drops back to the options to save the message without […]


Elastix Asterisk 2.7 FreePBX configure extension to use specific outbound trunk

I have my home phone as well is business phones running through the same server. I –


Asterisk command line interface (CLI) commands

Below are a list of commands you can use from the Asterisk command line interface (CLI) The CLI is reached by using the Linux shell command asterisk-


Script to backup Asterisk folders

The key folders to backup for asterisk are /etc/asterisk /var/log/asterisk /var/lib/asterisk /var/spool/asterisk /usr/lib/asterisk /var/lib/mysql /usr/local/tomcat/webapps You can use this script to back them up into one gz file. ora=`date ‘+%Y.%m.%d-%H.%M.%S’` tar zcf etc-asterisk-$ora.tar.gz /etc/asterisk tar zcf var-log-asterisk-$ora.tar.gz /var/log/asterisk tar zcf var-lib-asterisk-$ora.tar.gz /var/lib/asterisk tar zcf var-spool-asterisk-$ora.tar.gz /var/spool/asterisk tar zcf usr-lib-asterisk-$ora.tar.gz /usr/lib/asterisk tar zcf var-lib-mysql-$ora.tar.gz /var/lib/mysql tar […]


How to Backup and restore Elastix Asterisk configuration on Cent OS to another server

I recently found this method of doing the backup/restore A few things to be aware of Make sure the Elastix version is the same or higher than the version that you are transferring the backup .tar file from. Otherwise if you try to transfer to an earlier version the extensions will not transfer across […]


Configure Acrobits SIP iphone app to externally access 3CX VOIP server so RTP voice traffic works

If you are trying to get Acrobits SIP phone working on your iPhone with the 3CX VoIP telephone system use the settings indicated below. For the domain entered the local network DNS name of the server i.e. what is used to connect to 3CX on the local network. For Register via leave the default setting […]


Asterisk Music on Hold MOH Sound Choppy in and out using Pennytel and engin

When we put a call on hold using out asterisk server the Music on hold would chop in and out. We found this choppiness only occurred using Pennytel and Engin, other VOIP providers the MOH was smooth. Try this: Make sure you’ve compiled zaptel and have ztdummy loaded. Login to the server. If connecting from […]