I tried a lot since yesterday but maybe not the right things to do that what i want.
My openwrt Router(192.168.1.1) is connected via Lan with the Main Modem Router(192.168.0.1) and the internet works fine. I also connected a usb storage that works fine with mini dlna. I can access the dlna Server from all devices that are connected with the openwrt router but i cant access the server from the main modem.
Please help me because i am realy desperate. Thanks a lot😃
If you trust the wan side of the OpenWrt, you could allow INPUT from wan firewall zone.
Otherwise you'll need to allow the ports tha dlna uses on wan zone.
For full network access you could run OpenWrt as a LAN device, that is put it in the main router's network. This means that OpenWrt would be a file server. You can add other functionality such as a WiFi AP ("dumb AP").
All users on the LAN would route to the Internet directly through the main router, and they would all be in one pool of IP addresses.
It all depends on whether you need OpenWrt router to have its own subnet (as you have it now, by connecting the cable to the WAN port), in which case the solution would be what @trendy said. Though I would opt for forwarding the dlna port ONLY, (and possibly SAMBA) because of you were willing to allow all input from WAN then you probably shouldn't have connected the cable to the WAN port on the first place.
And this takes its to connecting the cable to a LAN port, in which case the router will just act as a switch, AP and whatever services you need such as file or media server, as @mk24.
So it's all up to your network design and requirements.