Serviio

Hi. Is there a way to open some port(s) on NAT (router) and transit DLNA over it? I have client behind NAT and Serviio on the other side and want to play video.

No, DLNA is designed to work over a Local Area Network (LAN) and will not work across the internet. You could always try:

• Extending your LAN across the internet by using a VPN. Even though a VPN will allow DLNA to work, DLNA is not optimized for the internet and unless you have good bandwidth and limited hops (eg. both ends on the same provider) you probably won't get an acceptable experience; or
• Use Serviio Mediabrowser or ServiiGo. Both are designed for use via the internet.

I don't want to use DLNA over internet - it is in my LAN but there is second router and player (RaspBMC) is behind this router and Serviio is on the other end.

Sorry, misunderstood what you were asking. Normally only worry about ports on a router when accessing the internet.

Yes it may be able to be done (and if you want to go that way let me know and shall endeavour to help, but a warning - it is not something you want to do unless you are really comfortable with networking, and even then it depends on your routers and their capabilities) but it's much, much simpler to simply convert the second router into a switch.

I presume at the moment you have a cable between the LAN port on Router 1 connected to the WAN port on Router 2. To convert Router 2 to a switch simply:

• Turn off DHCP on Router 2.
• Connect a cable between the LAN port on Router 1 connected to the LAN port on Router 2 (not the WAN port. The WAN port on Router 2 should not be used for anything).

Thats all there is to it. You may need to reboot devices on Router 2 so that they get there new gateway and internal IP's but it should all work fine after that.