Port forwarding

Is it possible with IP-port forwards to get access to a free version of Serviio from on another network?
I have two networks a Wifi and a Lan. Serviio is running on the Lan and I want to have access to Serviio from the Wifi network.
I have had perfect access to Serviio from Wifi, because the Lan and Wifi was the same network. Now with a new fibernetwork router I can't do that. I have to split in two networks. The router for the Lan is an old Linksys WRT54GP2 configured with VOIP. I have not figured out how to configure it as a switch, which will create one network with the same IP-range. The fibernetwork router has only one port for Lan and DHCP, so it's possible to have on IP-range.
I have tried forwarding the following ports to the Serviio server with out success:
I have two networks a Wifi and a Lan. Serviio is running on the Lan and I want to have access to Serviio from the Wifi network.
I have had perfect access to Serviio from Wifi, because the Lan and Wifi was the same network. Now with a new fibernetwork router I can't do that. I have to split in two networks. The router for the Lan is an old Linksys WRT54GP2 configured with VOIP. I have not figured out how to configure it as a switch, which will create one network with the same IP-range. The fibernetwork router has only one port for Lan and DHCP, so it's possible to have on IP-range.
I have tried forwarding the following ports to the Serviio server with out success:
- 8895
- 1900
- 23423 and
- 23424