What is unplumb and plumb of ifconfig?

[Ricky_4]

Hi All,

What is the use of unplumb and plumb of ifconfig? Where and when should I use?

Your replies will clear our my confusions on this ifconfig options.

Thanks.

Adriatico

[Sridhar Bhaskarla · Accepted solution]

Hi Adriatico,

plumb/unplumb enables/disables streams on that interface.

When run, "unplumb" detaches the IP address from that interface. Plumb is automatically done when you add the IP address. While plumb is not explicitly used in day-to-day operations, unplumb is used to remove the IP address from the interface.

-Sri

[Ricky_4]

Hi,

Thanks for your replies.

So it will remove all the ip addresses bound on that interface once you unplumb.

Regards,

Adriatico

[rick jones]

Plumbing and unpluming is when IP is "connected" to DLPI - connecting the plumbing as it were. This "connecting" is binding the IP and ARP SAPs to the NIC so the driver will start passing IP and ARP packets up to IP and (surprise) ARP.

Once an interface is plumbed, you can assign IP addresses to it. On HP-UX, the first "ifconfig lanN" does an implicit plumb operation so it is uncommong to acctually issue a "plumb" directly. Also, on HP-UX, an unplumb will do an implicit deleting of IP addresses. (IIRC)

[Muthukumar_5]

plumb and unplumb is differed based on primary interface name and secondary interface name.

primary interface - lan0
Secondary interface - lan0:1

See more on ifconfig man page for "IP Index Number" part

By default,

plumbing is made setup after configuring the ip-address to any type of interface so that streams on TCP / IP to be used.

unplumbing is used to remove the configured ip-address on the interface. Here it is differeing based on iterface as,

primary interface - it is unplumbig the interface at once so that streams with tcp/ip is disabled.

secondary interface - it will get in effect by assigning ip-address to that interface as 0.0.0.0 ( ipv4 ) :: ( ipv6 )

you can view these changes with netstat -in command execution