Hello Pirmin,
after testing lighttpd.run myself I discovered that the run script can't work in your scenario.
First, it expects a running DHCP server on tap0 - tshark was my friend here. Changing the nic_router config for uplink to
<domain name="uplink" interface="10.0.2.55/24" gateway="10.0.2.1">
made the nic_router functional - ping 10.0.2.55.
But, the script also sets up the VFS of lighttpd with a statically configurted <lwip> node for 10.0.2.55 which contradicts the nic_router config. A quick test with
proc socket_fs_plugin { } { return {<lwip dhcp="yes"/>} }
made the script working again.
I'll prepare a patch for staging.
Greets