Hey, anyone can help on this it would be very appreciated.... I tried moving my internal networks to Mikrotik NAT from Cisco NAT. Everything seemed ok. But I just found out that VOIP is now completely broken. Customers VOIP boxes, Grandstream, Linksys, etc. cat get on the VOIP server for setup, can establish calls, but there is no ringtone ( there is dialtone), and there is no voice, either direction.

We have tried both a block nat (/24) and dedicated NAT /32. We are running the firewall on 3.11. Huge problem for us! We need to move beyond the cisco.

Robert

Need more info, Are you using one lan interface and one wan?
Are the requests coming from the outside(wan) to the inside (lan)

I have a 1wan 1lan setup and VOIP works fine. I can register to the work VOIP server and stuff can register to my voip box.

Who is your VoIP provider? Do you have a network diagram?

There is one Wan interface and one lan interface. Fairly simple. The VOIP provider is SipTalk http://www.siptalk.com, works fine on the cisco, doesn't work on Mikrotik. Can turn the NAT on the Mikrotik off and on and voice and dialtone come and go. Note that Vonage works. I have been trying to get to someone at Siptalk to see what they are doing different, but nobody seems to be home.

try disabling sip helper in ip-firewall-service ports

I second the above, I belive the sip helper stopped working around version 3.9 or 3.10, have had to turn it off since.

Sorry, I should have posted that I have tried with the sip helper off and on. No difference...

The SIP helper is still not worth a squirrel fart in 3.14.