plumb , unplumb

[khilari]

Hi people, what does plumb means. ifconfig lan1 plumb or unplumb. What is it doing.
Thanks

[Geoff Wild]

Taking it up/down.

From man page:

plumb Setup the Streams plumbing needed
for TCP/IP for a primary interface
name. (See the Interface Naming
subsection given below.). By
default, the plumb operation is
done automatically when an IP
address is specified for an
interface.

unplumb Tear down the Streams plumbing for
a primary interface name. (See
the Interface Naming subsection
given below.) Secondary interface
does not require "plumbing". A
secondary IPv4 interface can be
removed by assigning an IP address
of 0.0.0.0 to it. Remove a
secondary IPv6 interface by
assigning an IP address of :: to
it.

Rgds...Geoff

[Ninad_1]

Hi,

What plumb and umplumb really mean is setting up streams or destroying streams required for the TCP/IP to use the interface port - basically if you are aware of the term binding and unbinding.
I guess its something to do with the Transport layer in the OSI model - in the Transport layer, the streams of data are split into packets - to enable this functionality of the TCP/IP its required to bind with a port and for that you use plumb/and to unbind use unplumb.
I have understood this much only, if anyone has a better understanding, I am also interested in knowing.

Regards,
Ninad

[rick jones]

What it boils down to, apart from instantiating the "interface" at the transport level in the first place and making/severing a Streams association between IP/ARP and the driver, is the binding or unbinding of the IP and ARP SAPs from the driver/interface.

Unplumbing an interface would mean that one could have an alternate IP stack run over the interface.