X Lite and Express Talk not connecting to Asterisk Server

I am currently learning Asterisk so please go easy on me :smile:

I have an Ubuntu 14.04 Server installed via Virtual Machine in Windows 7 all 64 bit and installed Asterisk 13 in the virtual server but it seems that my softphones (X Lite and Express Talk) cannot register, error 408 pops up and when I configure the phones to the right credentials, turn off the AV, X Lite shows enabled but after 2 seconds it suddenly tried to enable again and cannot register itself afterwards, what did I do wrong? :confused:

My network setup is we have a modem router which acts as DMZ(it came from our ISP and it is loaded with defaults so we cannot configure it security wise) which has wireless disabled connected to the secure Cisco E1200 which acts as our main router, is this because of Asterisk’s NAT issue?

408 means that there was no reply at all.

Are you should that both VMs aren’t competing for port 5060?

Is a firewall blocking it?

Does “sip set debug on” show the request arriving at Asterisk?