Csdrhrt

I have the Raspberry Pi 2, and the official WiFi dongle that comes from the makers of Pi. I'd like to mention that I'm very new to understanding technology, code, and how things work in general so I may be trying to do something that's entirely impossible.

I was wanting to set up a sort of private router on the Pi in my room nearby, but noticed that all the tutorials for setting up Pi routers are for when you're connected to the main router via eth0.
My question is: Is it possible for other devices to connect to the Pi like a router, and have all the traffic go through wlan0 to the main router and back?

I'm guessing that modifying the tutorials to apply to wlan0 could be what I'm asking, but I'm unsure if you can even have wlan0 as both an access point for other devices and the Pi's own connection to the internet at the same time. I feel like to someone with actual understanding of the topic, this may seem a very stupid question, so I apologise in advance.

Thanks

This would infact be possible. If you strictly wanted to avoid using the physical network port, then you could have a second wireless adapater which would become wlan1.

If you think about your actual router, it has an Internet connection which is the WAN side, and internal network ports which are on the LAN side. (It may also have a wireless network card, connected to an antenna which is generally also on the LAN side.).

I'm unsure if you can even have wlan0 as both an access point for other devices and the Pi's own connection to the internet at the same time.

With two wireless adapters in the Pi, one could be the WAN side of your Pi router; the side that connects to the actual router, which in turn connects to the Internet. The other would be the LAN side; this is what your laptop or tablet connects to.

If you are able to connect the LAN cable you could still do the following with eth0 and wlan0:

The Raspberry Pi forum has a thread about two wifi adapters which should get you to the stage where you can ifconfig wlan0 && ifconfig wlan1.

One of these adapters, say wlan0, should get an IP address from the actual router. For testing the other should probably have a static IP which might connect to your laptop, also on a static IP.

To give the Pi some actual router functionality, check out the arch linux Internet Sharing Wiki. Even if you're not using arch these steps should be similar.

Another guide takes it down to a few steps:

First you need to tell your kernel that you want to allow IP forwarding.

echo 1 > /proc/sys/net/ipv4/ip_forward

Then you'll need to configure iptables to forward the packets from your internal network, on /dev/wlan1, to your external network on /dev/wlan0. You do this will the following commands:

# /sbin/iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

# /sbin/iptables -A FORWARD -i wlan0 -o wlan1 -m state

   --state RELATED,ESTABLISHED -j ACCEPT

# /sbin/iptables -A FORWARD -i wlan1 -o wlan0 -j ACCEPT

You should now have full internet access from your laptop, provided the default gateway is set to the static address of wlan1.