Given that the VPN server (which will route our traffic to the world wide web) has the address 132.195.255.200 and the WiFi interface is wlan0, the following IPTables rules make sure that:

• No new connections come in over WiFi
• Outgoing traffic on the WiFi interface is prohibited except for VPN access and the local network (providing DNS and the gateway to the VPN server)
• Everything else is untouched

# Flush tables we care about
iptables -F INPUT
iptables -F OUTPUT
iptables -P INPUT -j ACCEPT
iptables -P OUTPUT -j ACCEPT

# DROP any new connections from outside, stil lallow all established
iptables -I INPUT -i wlan0 -m state --state NEW -j DROP

# DROP anything going out over pure WLAN except VPN and the local network ( + DHCP)
iptables -I OUTPUT -o wlan0 -d 132.195.255.200 -j ACCEPT
iptables -I OUTPUT -o wlan0 -d 81.163.0.0/16 -j ACCEPT
iptables -I OUTPUT -o wlan0 -p udp --dport 67 -j ACCEPT
iptables -I INPUT -i wlan0 -p udp --dport 68 -j ACCEPT
iptables -A OUTPUT -o wlan0 -j DROP

This way, you can feel free to do anything you like without risking your excited fellows taking a too close look .

Update 16:45: Added DHCP rule!

Einem Augenzeugen zufolge war der Bus schon in Keilbeck (ca. 1km vor dem Unfallort) durch erhöhte Geschwindigkeit aufgefallen.

Berichte:

Oberberg Aktuell
RTL Aktuell
Stadtnetz Radevormwald
RP Online
N24
WZ Newsline
Bild.de (Video)