Hi, i'm new to openwrt and have some issues configuring the software update list in administration.

First my setup:

Internet <-> Upc/Ziggo modem/switch  <-> Tp-link <-> devices.

The ziggo modem has a static ip 192.168.1.1
The ziggo modem is configured as dhcp server starting the pool from 100

OpenWrt Chaos Calmer 15.05.1 / LuCI 15.05-149-g0d8bbd2 Release (git-15.363.78009-956be55)
The tp-link has a static ip: 192.168.1.2
Dhcp disabled.
Disabled the vlan functionality for now.
I don't use the wan port of the tp-link. just port 1 and 4 (for now)

I have added the ipv4 gateway to the LAN interface and also filled in the google dns servers as well as the dns servers of my own provider.
Also added the DNS server ip's to the DNS forwardings section in the DHCP and DNS general settings.

Accesed the TP-link via ssh (Putty 64-bit)
And when i try to:
root@OpenWrt:~# ping downloads.openwrt.org
i get:
ping: bad address 'downloads.openwrt.org'

And when i try the ip adress of that url i get:

root@OpenWrt:~# ping 78.24.191.177
PING 78.24.191.177 (78.24.191.177): 56 data bytes
ping: sendto: Network is unreachable

But i CAN ping it from a device from a dos box.
(I can use all my devices normally with internet)

I am trying to get the software lists to update as i want to install znc om my router for irc.

However when i try to update the software list i get the error:
wget: bad address 'downloads.openwrt.org' wget returned 1

Any tips/advice on what i do wrong ?