vmnet(1) · carta

NAME

vmnet — A simple virtual networking program

SYNOPSIS

vmnet

DESCRIPTION

This manual page documents briefly the vmnet program.

This manual page was written for the Debian GNU/Linux distribution because the original program does not have a manual page. Instead, it has a README file; see below.

This program has been written to implement virtual networking support for the Hercules S/390 simulator, but it is intentionally generic in its functionality, so any other virtual machine simulator/emulator program could potentially use it.

The function is quite simple: The virtual machine simulator program starts VMnet and talks the SLIP protocol with it over stdin/out. VMnet sets up a SLIP connection on the host system, talking over a pseudo-tty to the VMnet program. Once things have been set up, VMnet simply copies the data streams between stdin/out and the SLIP psuedo-tty in both directions. Thus, the virtual machine has a direct SLIP connection with the host, without needing to worry about root privileges, pseudo-ttys, access rights, etc.

CONFIGURATION

You will need to create a configuration file /etc/vmnet.conf with entries that look like:

user remote-ip local-ip command

Each entry/line in the file represents a pair of IP addresses that a given user may use. Lines starting with "#" are ignored.

The user field identifies the user by her login name.

The remote-ip field contains the remote IP address, as seen from the SLIP connection on the host, i.e. the IP address of the virtual machine.

The local-ip field contains the local IP address, as seen from the SLIP connection on the host. You may have to specify this address as the "remote address" or "gateway" on the virtual machine.

The command field gives a command to be executed when the SLIP interface is brought up or down. The command should accept three arguments: (up|down), remote-ip, local-ip. This can be used to perform any special actions, like routing, proxy-arp, etc, as needed. You must specify a valid command here. If you don't want anything done, "/bin/true" will do.

OPERATION

The user will normally not run the vmnet program manually, unless he wants to practice his skills at reading and typing SLIP packets. The intended usage is to have the virtual machine start vmnet at the appropriate time so it can connect the stdin/stdout of vmnet to its network device simulation. When VMnet is started, it expects one line of input, containing the remote-ip address to use, followed by SLIP traffic. VMnet does not produce any user-readable output on stdout.

AUTHOR

vmnet was written by Willem Konynenberg [email protected]