I am posting this as I have ran into a few issues and these are things I have found that help.
1. Always statically assign the Grandstream
2. Go to (IP Blacklist) and whitelist the Static IP - Sometimes the 3cx will block the IP
3. Make sure the customer does not have port 5060 blocked internally. If they do the work around is to put a dummy switch and plug your 3cx box and the Grandstream into that with one cable going to their network. This will allow the Grandstream to register with the 3cx and still be on the customers network.
Jason
1. Always statically assign the Grandstream
2. Go to (IP Blacklist) and whitelist the Static IP - Sometimes the 3cx will block the IP
3. Make sure the customer does not have port 5060 blocked internally. If they do the work around is to put a dummy switch and plug your 3cx box and the Grandstream into that with one cable going to their network. This will allow the Grandstream to register with the 3cx and still be on the customers network.
Jason
