Hello again, this is a special request since is a very complex from my point of view setup so any help will be very well appreciated.
I have a Grandstream VoIP PBX, connected to my Mikrotik. This PBX is setted up in DUAL mode to be able to use two different SIP providers.
On the WAN interface from PBX there is one of the SIP providers configured, on the LAN is the internal LAN network and in one Mikrotik port is setted up the second sip provider. this was the only solution that i've found in order to be able to connect two different SIP providers in one two ports Grandstream UCM.
on the Mikrotik i have setted up SIP ALG since is the only way that i can have both ways audio, but i can only have a couple of SIP channels working because as soon as I have the third concurrent call, there is no audio in one way.
if I dissable SIP ALG i lost audio in every call.
I have setted up SIP ALG adding ports 20000 and 30000 since this feature does not allow me to ad a group of ports for example "20000-30000", i can only set up one by line until I reach 6.
if I dissable SIP ALG and NAT the ports 10000-20000 I lost audio.
I have no clue where I can be wrong, I have been trying several approaches, so any advise will be very well appreciated.
Thanks in advance.