@Marvin_S Thanks, i have another question i can't find anywhere. How long is the NAT refresh time? How many seconds? For how long a router keeps records in the NAT? I found this on internet:...

@Marvin_S I ask you how can I get this information and how to understand if the router has a symmetric nat or not. Thanks.

How do i know if the modem/router has a Symmetric NAT? This information is really important regarding VoIP, yet I can't find it anywhere, nor do I know how to get it. Can someone help me? I have a...

@Marvin_S What do you think is the best tp-link modem that I can buy with full compatibility for VoIP?

Advanced - Telephony - Telephone Numbers - Modify - Advanced, here i can't find the preferred codec to set for my VoIP, where I could choose between G.711, G.722 etc... I have always found these...

@terziyski thank you, I hope to solve the problem as soon as possible