Enable RTP-UDP (port range is 10,000-20,000).
- Enable SIP-UDP/TCP port 5060.
- Make sure that there is no SIP inspection/SIP transformations enabled depending on your firewall.
- Turn off ALG (Application Layer Gateway).
- To automatically instruct the phone with the provisioning URL you need to program ‘option 66′ on your DHCP server with the following address “http://cprx3.hostedsip.net/pv”.
- Apply QOS on your firewall or router
Firewalls with Known Issues
Hitron CGN3 (Rogers):
Compatibility: NOT Compatible
Status: This router does not have the ability to disable SIP ALG and is not compatible with VoIP. This router will need to be replaced with a router that is compatible. If you check the Hitron web site they suggest it is possible to place a phone on the DMZ, but, this is not advisable as it will compromise the security of the phone.
Cisco Routers (general)
Status: Cisco is the most common router available. These routers may require some changes (see above).
Compatibility: Compatible after changes
Recommendation: Disable SIP ALG and ensure appropriate firmware (see below)
Status: The following changes (or checks) are required:
1) Must be running firmware v3.3 or above
2) Must disable SIP ALG