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I have a TP C3200 Router. Connected to it is an Obihi 200 VOIP box. The Obihai had been working for 9 months flawlessly. It stopped working. In trouble shooting it, the Obihai team directed me to enable DMZ. I enabled it and pointed it to the LAN network IP address 192.168.0.1. The Obihai is now working again. My questions
1-Is enabling the DMZ a safe thing to do?
2-Does it sound right that the Obihai stopped working and I had to set something in the router to get it to work again?
3-Is the LAN network the best choice to point the DMZ to?

Thanks Bill