Symetric NAT?

Hi,
I am trying to configure a sipx PBX with mikrotik and a sip trunk provider.
They say that i should have symetric nat in between.. but i’m not sure how to configure it.. i have played with the nat rules, but i’m no sure if that’s ok..

add action=dst-nat chain=dstnat comment=“” disabled=no dst-address=
10.160.250.62 dst-port=5080 protocol=udp to-addresses=192.168.1.6
to-ports=5080
add action=dst-nat chain=dstnat comment=“” disabled=no dst-address=
10.160.250.62 dst-port=5070 protocol=udp to-addresses=192.168.1.6
to-ports=5070
add action=dst-nat chain=dstnat comment=“” disabled=no in-interface=ether3
protocol=udp src-port=5060 to-addresses=192.168.1.6

can sobebody tell me how to configure symetric nat on mikrotik?
thanks..

The rules you posted will work for internal redirections. If you want all traffic to a particular IP to always go to the same host you could use the following.
http://wiki.mikrotik.com/wiki/Manual:IP/Firewall/NAT#1:1_mapping

/ip firewall nat
add chain=dstnat action=netmap dst-address=10.160.250.62 to-addresses=192.168.1.6
add chain=srcnat action=netmap src-address=192.168.1.6 to-addresses=10.160.250.62

Or use this if you still want to control access by port.

add chain=dstnat action=dst-nat in-interface=ether3 protocol=udp src-port=5060 to-addresses=192.168.1.6
add chain=dstnat action=dst-nat dst-address=10.160.250.62 dst-port=5080 protocol=udp to-addresses=192.168.1.6 to-ports=5080
add chain=dstnat action=dst-nat dst-address=10.160.250.62 dst-port=5070 protocol=udp to-addresses=192.168.1.6 to-ports=5070

add chain=srcnat action=src-nat protocol=udp src-address=192.168.1.6 src-port=5060 to-addresses=10.160.250.62 to-ports=5060
add chain=srcnat action=src-nat protocol=udp src-address=192.168.1.6 src-port=5070 to-addresses=10.160.250.62 to-ports=5070
add chain=srcnat action=src-nat protocol=udp src-address=192.168.1.6 src-port=5080 to-addresses=10.160.250.62 to-ports=5080

Thanks for your post..
I have tried both solutions, but i can’t see any packets going thru..
nothing happens.. :confused:

Try the suggestion from here.
http://forum.mikrotik.com/t/netmap/39413/5