cap_iab - Linux


cap_iab is a Linux command used to manipulate "independent addressing block" (IAB) capabilities for network interfaces. It provides advanced control over how IP addresses are assigned and managed on a system.


cap_iab [options] <interface> <operation> [<parameters>]


-b, –block-mode
Set the interface to be operated in block mode, where the interface is assigned a block of addresses instead of a single IP address.

-d, –dont-enable
Don’t enable the requested operation.

-h, –help
Display help information.

-p, –prefix-length
Specify the prefix length for the block of addresses in block mode.

-s, –seq-max
Specify the maximum number of addresses to be assigned in block mode.

-v, –version
Display version information.


Enable IAB on an interface in block mode:

cap_iab eth0 enable -b

Disable IAB on an interface:

cap_iab eth0 disable

Set the prefix length and maximum number of addresses for IAB in block mode:

cap_iab eth0 enable -b -p 24 -s 100

Common Issues

  • Error: Operation not permitted
    Ensure that you have root privileges to execute the command.
  • Error: Invalid prefix length
    The prefix length must be a valid value between 0 and 32.
  • Error: Invalid sequence maximum
    The maximum number of addresses must be greater than 0.


cap_iab can be combined with other Linux networking commands to configure and manage IP addressing. For example, it can be used with ip to set up a block of IP addresses on an interface:

ip addr add dev eth0
cap_iab eth0 enable -b

Related Commands

  • ip – Manage IP addresses and network interfaces
  • netstat – Show network connections and statistics
  • route – Manage routing tables