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
     ipforwarding in the dual stack IP driver to zero. This dis-
     ables IPv4 packet forwarding.





SunOS 5.11          Last change: 13 Mar 2009                    1






System Administration Commands                            ndd(1M)



       example% ndd -set /dev/ip ipforwarding 0




     Similarly, in order to disable IPv6 packet  forwarding,  the
     value of parameter ip6forwarding


       example% ndd -set /dev/ip ip6forwarding 0



ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Availability                 SUNWcsu                     
    


SEE ALSO
     nca(1), dladm(1M), 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 use of ndd to  administer  Layer  2  (Data  Link  layer)
     drivers  is strongly discouraged as this capability is to be
     obsoleted in a future release, replaced by dladm(1M). Please
     refer  to  the driver-specific man page in section 7D of the
     SunOS man pages.


     The meanings of many ndd parameters make sense only  if  you
     understand how the driver is implemented.




SunOS 5.11          Last change: 13 Mar 2009                    2






System Administration Commands                            ndd(1M)



     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.




















































SunOS 5.11          Last change: 13 Mar 2009                    3