The
sl interface allows asynchronous serial lines to be used as IPv4 network interfaces using the SLIP protocol.
To use the
sl interface, the administrator must first create the interface and assign a tty line to it. The
sl interface is created using the
ifconfig(8) create subcommand, and
slattach(8) is used to assign a tty line to the interface. Once the interface is attached, network source and destination addresses and other parameters are configured via
ifconfig(8).
The
sl interface can use Van Jacobson TCP header compression and ICMP filtering. The following flags to
ifconfig(8) control these properties of a SLIP link:
link0
Turn on Van Jacobson header compression.
-link0
Turn off header compression. (default)
link1
Don't pass through ICMP packets.
-link1
Do pass through ICMP packets. (default)
link2
If a packet with a compressed header is received, automatically enable compression of outgoing packets. (default)
-link2
Don't auto-enable compression.