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Currently, I have multiple android users connected to my server through TCP connection.

Each authorized users have an interface and an unique IP address between 10.0.0.0 … 10.255.255.255.

Whole user’s traffic as raw IPv4 data will pass to server from TCP connection then server will pass that data to a tun device then the data will forward through eth0, till now every thing is fine, Inside server I've to create a tun device for each users connected to server, So if I have 100 users the server have to create 100 tun devices.

I want to know is it possible to create a single tun device that handle a range of IP addresses ?

Ali Khazaee
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  • Wait, are you assigning those addresses to the tun interface _on the server_? They don't even belong there in the first place. – user1686 Apr 20 '23 at 09:32
  • At client side for user A the ip will be 10.0.0.1 and on the server side, I use same ip then the packet can be forwarded without any modification – Ali Khazaee Apr 20 '23 at 09:43
  • Right, okay, but why do you think you need something special on the server side at all? – user1686 Apr 20 '23 at 09:44
  • I just wanted to make my work on server side easy, and maybe incease performance issue – Ali Khazaee Apr 20 '23 at 09:53

1 Answers1

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I got this answer from ChatGPT.

Yes, it is possible to create a single tun device that handles a range of IP addresses in Linux. This can be achieved by using the tunctl command to create a tun device and then configuring it with the appropriate IP address range.

Here are the steps to create a single tun device that handles a range of IP addresses:

Install the uml-utilities package if it is not already installed.

This package contains the tunctl command that we will use to create the tun device.

sudo apt-get install uml-utilities

Use the tunctl command to create a new tun device. In this example, we will create a tun device named tun0.

sudo tunctl -t tun0

Assign an IP address to the tun device using the ifconfig command.

In this example, we will assign the IP address range of 10.0.0.0/24 to the tun device.

sudo ifconfig tun0 10.0.0.1 netmask 255.255.255.0 up

Enable IP forwarding on the server using the sysctl command.

This will allow the server to forward traffic between the tun device and the eth0 interface.

sudo sysctl -w net.ipv4.ip_forward=1

Configure the routing table to route traffic from the tun device to the eth0 interface. In this example, we will use the route command to add a route for the 10.0.0.0/24 network.

sudo route add -net 10.0.0.0 netmask 255.255.255.0 dev tun0
sudo route add -net 10.0.0.0 netmask 255.255.255.0 gw <eth0_ip_address>

By following these steps, you can create a single tun device that handles multiple IP address ranges in Linux. This can be useful for managing a large number of users on a server without having to create a separate tun device for each user.

Ali Khazaee
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