I am facing a peculiar problem with my current setup.

When I dial out using my voip provider (sipgate), I can call other people, they can hear me, but I cannot hear them. However, when they call me, everything works fine as expected, voice works in both directions.

Any pointers would be highly appreciated! My setup:
I have disabled the SIP Helper
I have no firewall rules except NAT everything out the PPPoE Client interface
See screenshot for complete config:

Try forwarding the RTP port that Linphone is using to the Linphone client using a destination NAT rule.

That did not work, however, forwarding all of the incoming UDP packets did work. I assume that the sipgate.de server is sending packets into my interface on a port that mikrotik does not know about, and as a result, the packet gets dropped. Is this what the sip helper is for? If yes, I am out of luck, since enabling it did not work. Any more elegant way to solve my problem? Right now I can only use one device behind my NAT to phone someone, but I want to be able to use multiple devices...
Thanks!

Can You show Your filter rules?

There is some info from Sipgate at:

http://www.sipgate.com/faq/article/709/ ... _a_network

Essentially each SIP end point needs to use a distinct SIP and RTP port within the ranges that Sipgate supports - then you forward the ports accordingly on the firewall.