cannot mount via nfs after network change

[dbbd]

My home router was replaced, and now my whole network is on a new subnet (10.100.102.x).
Since then, my ubuntu fails to nfs mount the nas volumes.
showmount -e nas gives me:
clnt_create: RPC: Port mapper failure - Unable to receive: errno 111 (Connection refused)
rpcinfo gives:
rpcinfo -p nas
rpcinfo: can't contact portmapper: RPC: Remote system error - Connection refused

Obviously my freenas IP addresses were all changed to the new subnet (dhcp is used) and so did the ubuntu client. Ping works well.
I'm pretty sure I need to fix something in the freenas config, but have no idea what and how to debug this.

Please help?

 

[SweetAndLow]

You should configure the gateway option under the network settings. Also you should know your jails will need a similar modification if you have any.