ndd -h

[Bill McNAMARA_1]

Can someone give an brief overview on the importance of ndd and /etc/rc.config/nddconf

Thanks!
Bill

[Marcin Wicinski]

Hi Bill,

Rather then providing this functionality via kernel parameters, the network parameters that can be tuned are available via HP-UX commands.At 11.0, the command is ndd,
while at 10.20 the command is nettune.To make permanent changes that will remain after the reboot for 10.20 will require that the administrator write a startup script that will execute the nettune command. In 11.0, this
functionality is built into the /sbin/init.d/net startup script. To
make permanent changes to the default ndd configuration, edit the file
/etc/rc.config.d/nddconf.

[Michael Duthie]

At 11.0, the command is ndd(1M),
while at 10.20 the command was nettune(1M). The man pages for each will
explain how to make these changes at the command line. It is used for changing the network "keepalive" settings, tcp_keepidle, tcp_keepintvl, and tcp_maxretry. However, these changes will only last until the system is rebooted. To make permanent changes that will remain after the reboot for 10.20 will require that the administrator write a
startup script that will execute the nettune command. In 11.0, this functionality is built into the /sbin/init.d/net startup script. To
make permanent changes to the default ndd configuration, edit the file /etc/rc.config.d/nddconf.

[Magdi KAMAL · Accepted solution]

Hi again,

Here how to set ndd to Zero:

TRANSPORT_NAME[0]=ip
NDD_NAME[0]=ip_pmtu_strategy
NDD_VALUE[0]=0

Here how to set ndd to One:
TRANSPORT_NAME[0]=ip
NDD_NAME[0]=ip_pmtu_strategy
NDD_VALUE[0]=1

You can modify the "Don't fragment" bit dynamicly without boot.

The command to set ndd to 0 :
ndd -set /dev/ip ip_pmtu_strategy 0

The command to set ndd to 1 :
ndd -set /dev/ip ip_pmtu_strategy 1

Magdi

[Magdi KAMAL]

Hi Bill,

ndd is used to set the "Don't fragment" bit in tcpip protocol.

When you have network topology which include more that one protocol, sometime you need to tune whether fragmenting or not ( for better performance ).

hp-ux 11.0 had changed it to value ONE ( actif ) silently without any notice and this causes alot of network traffic problems.

By setting it to zero, we got our usual performance.

Magdi

#########

This is the first response .. there was a problem .

The second is above.
sorry

Magdi

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[rick jones]

ndd is important IFF you feel the need to change various networking paramters from their defaults. the nddconf file is important IFF you want those changes to be applied on each reboot of the system.

otherwise, ndd/nddconf aren't terribly important, but you should _NOT_ remove them from the system. at the least it would probably annoy the startup scripts, and at worst, it might (because the scripts were annoyed) preclude a successful start of networking.

ftp://ftp.cup.hp.com/dist/networking/briefs/annotated_ndd.txt