OpenBSC behind NAT

[Seungju Kim]

Hello, i am trying to set up an openbsc network behind NAT. So far i can run 
the bts with oml/rsl. But the bts fails to connect to the sgsn. I think it is 
because of the ports. What ports shall i open in order to get it work? And the 
encalsulation settings could not be matched because the sgsn is behind the nat. 
Is there a workaround for this?