SIP

i m using grandstream UCM6204 as IP PBX conncted to internet over fortigate 90D as firewall. the IP address of this UCM is 10209.239.250 for IP phones connected inside the LAN phones are working fine no issue.

for phones connected using public IP address of the UCM we have many issue starting from no voice at the called number.

i have suspect the bandwidth but according to some troubleshoting it seem the issue is related to the firewall setting.

any support is realy apreciate