System Administration Commands ndd(1M)
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.
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 spe-
cial 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 dis-
ables 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 0
To view the current IPv4 forwarding table, use the following
command:
example% ndd /dev/ip ipv4_ire_status
To view the current IPv6 forwarding table, use the following
command:
example% ndd /dev/ip ipv6_ire_status
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
nca(1), ioctl(2), attributes(5), arp(7P), ip(7P), ip6(7P),
tcp(7P), udp(7P)
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 pro-
grams should avoid making dependencies on it.
The meanings of many ndd parameters make sense only if you
understand how the driver is implemented.
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