Networking

To set up a computer network, use network connectors and network cables to connect the connectors. Finally, make sure a network interface card is installed in each computer that should be part of the network.

Connectors have to be attached to any face but the front face of a computer. This allows the network card installed in it to send and receive packets through the connector.

Connectors connected with cables will forward packets to each other. For more complex network setups, a network hub may be necessary. It allows connecting multiple connectors with each other.

Network packets can only travel a certain maximum number of "hops". A hop can generally be understood as a single forwarding operation. For example, a connector forwarding a packet uses one hop. A network hub forwarding a packet to each connector the packet did not arrive from uses one hop. Once the number of remaining hops reaches zero, the packet is no longer forwarded. This avoids packets going in circles forever for networks with cycles. That said, this is a safeguard mechanism. No network should contain cycles, as this will also lead to the same packet arriving multiple times on receiving computers.

To set up a computer for networking, first ensure a network card is present. After this, using the default Linux distribution, run the command setup-network.lua. This will provide a wizard to configure how the computer should connect to the network. Alternatively, if you know what you're doing, set up network as you would on any regular Linux installation.

DHCP is a protocol which allows a simplified network setup. Only one computer will need to have a statically configured network address, all other computers in the network may have their addresses assigned to them automatically. When going for this setup, ensure there is only a single computer that acts as a DHCP server. Also ensure that no computer uses a static IP address that falls into the range of dynamically distributed IP addresses.

setup-network.lua starts the DHCP server when you configure a computer as one. It does not survive a reboot. See the "Daemons" section below for how to start it again, or how to make it start on its own.

Once you have a network setup running, with multiple computers in one network, you have all the options in the world. For example, you can copy files between computers using scp, log in to a remote computer using ssh and write custom network programs in Lua using the socket library. For samples on how to use the socket library, please see the samples in the official repository.

Note that scp and ssh are the client tools. Connecting to a computer from elsewhere needs a server running on it. See the "Daemons" section below.

For access outside the game, a network needs an internet gateway on it. Computers then use their ordinary network interface cards and route through it.

The gateway offers no DHCP and no name server, so set an address, a route and a name server yourself. See the internet gateway entry for an example.

The network daemons are shipped but not started at boot. Start the one you need by hand:

/etc/init.d/dropbear start for the ssh and scp server

/etc/init.d/telnet start for the telnet server

/etc/init.d/dnsmasq start for the DHCP server

The ssh server refuses to let anyone in while an account has a blank password, which is what root ships with. Set one with passwd before connecting for the first time. The telnet server has no such restriction, and accepts the blank password as-is, so anyone who can connect to the computer can log into it.

None of these survive a reboot. To start one at boot, give its script a boot-sequence prefix: