Hello I'm testing softphones to connect back Elastix from home, the following is what I tested: Softphone to Softphone = OK Softphone to PSTN phone = one way voice (PSTN can't hear Softphone) I tested two Elastix 1.6.0 and 1.5.2. The Elastix 1.6.0 installed OpenVox A400P with 3 FXO and the Elastix 1.5.2 installed TDM400P with 1 FXO. Two system installed on desktop motherboard. (1.6.0 installed on Intel DG41RQ and 1.5.2 installed on old Intel celeron motherboard. Also tested two firewall on this issue (Untangle and WatchGuard), but still cannot fix it. Firewall port forward: 5060 TCP UDP 10000-20000 UDP SIP_nat.conf nat=yes externhost=x.x.x.x localnet=172.16.0.0/255.255.254.0 externrefresh=10 How can I fix this issue ? Thanks !