NDD(8) Maintenance Commands and Procedures NDD(8)
NAME
ndd - get and set driver configuration parameters
SYNOPSIS
ndd [
-set]
driver parameter [
value]
DESCRIPTION
ndd gets and sets selected configuration parameters in some kernel
drivers. Currently,
ndd only supports the drivers that implement the
TCP/IP Internet protocol family. Each driver chooses which parameters
to make visible using
ndd. Since these parameters are usually tightly
coupled to the implementation, they are likely to change from release
to release. Some parameters may be read-only.
The
ndd command is deprecated. To manage Layer 2 (Data Link Layer)
properties use
dladm(8). To manage Layer 3 and Layer 4 Properties
(e.g. IP, TCP, UDP) use
ipadm(8).
If the
-set option is omitted,
ndd queries the named
driver,
retrieves the value associated with the specified
parameter, and
prints it. If the
-set option is given,
ndd passes
value, which must
be specified, down to the named
driver which assigns it to the named
parameter.
By convention, drivers that support
ndd also support a special read-
only
parameter named ``
?'' which can be used to list the parameters
supported by the driver.
EXAMPLES
Example 1: Getting Parameters Supported By The TCP Driver
To see which parameters are supported by the TCP driver, use the
following command:
example%
ndd /dev/tcp \? The parameter name ``
?'' may need to be escaped with a backslash to
prevent its being interpreted as a shell meta character.
The following command sets the value of the parameter
ip_forwarding in the dual stack IP driver to zero. This disables IPv4 packet
forwarding.
example%
ndd -set /dev/ip ip_forwarding 0 Similarly, in order to disable IPv6 packet forwarding, the value of
parameter
ip6_forwarding example%
ndd -set /dev/ip ip6_forwarding 0SEE ALSO
ioctl(2),
arp(4P),
ip(4P),
ip6(4P),
tcp(4P),
udp(4P),
attributes(7),
dladm(8), ipadm(8)
NOTES
The parameters supported by each driver may change from release to
release. Like programs that read
/dev/kmem, user programs or shell
scripts that execute
ndd should be prepared for parameter names to
change.
The
ioctl() command that
ndd uses to communicate with drivers is
likely to change in a future release. User programs should avoid
making dependencies on it.
The meanings of many
ndd parameters make sense only if you understand
how the driver is implemented.
If a TCP driver sends a report that is truncated, it could be because
that driver uses
ndd for transporting the report.
ndd imposes a 64K
limit on such reports.
September 15, 2024 NDD(8)
