By default access to UDP port 69, that is used for TFTP, is blocked by iptables (firewall) on SysAdminMan VPS server. This needs opening if you want to use Endpoint Manager to configure your compatible handsets.
When allowing TFTP access we only want to allow fixed IP addresses as there is no security provided by TFTP. You will probably also want to allow NTP (network time protocol) access to allow your Asterisk server to set the correct time on the phone, so we also open port 123.
Run the following commands while logged on as root. Replacing the address (184.108.40.206) with your own public IP address –
If you’ve installed Asterisk and FreePBX, or you’re using one of the preconfigured distributions such as Trixbox or Elastix, a good idea is to have the linux firewall, iptables, running on your system. Here’s an example of how you could set this up.
First thing to note is that it’s pretty easy to lock your self out of your server when playing around with iptables! It’s best to take a couple of simple precautions in case this happens.
These instructions should apply to CentOS/Redhat/Fedora.