TCP tuning

[vaman]

On HP_UX 11 how can I monitor the n/w status in terms of sockets, & fine tune tcp parameters like tcp/ip time out. Any info on tcp/ip fine monitoring & finetuning

[Sanjay_6]

Hi Vaman,

You can use ndd to finetune tcp parameters.

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90681/B2355-90681_top.html&con=/hpux/onlinedocs/B2355-90681/00/02/215-con.html&toc=/hpux/onlinedocs/B2355-90681/00/02/215-toc.html&searchterms=ndd&queryid=20041101-151756

Hope this helps.

Regds

[Sridhar Bhaskarla]

Hi Vaman,

The command 'ndd' will help you with finetuning. 'ndd -h' will give you all parameters that can be tuned. You decide on what to modify. These are what I presently configure on my systems mostly for security purposes rather than performance.

Transport Parameter Value
IP ip_forwarding 0
ip_ire_gw_probe 0
ip_pmtu_strategy 1
ip_send_redirects 0
ip_send_source_quench 0
ip_check_subnet_addr 0
ip_respond_to_echo_broadcast 0
ip_respond_to_timestamp_broadcast 0
ip_respond_to_address_mask_broadcast 0
TCP
tcp_conn_strategy 0
tcp_text_in_resets 0
tcp_conn_request_max 4096
tcp_fin_wait_2_timeout 1200000

-Sri

[Stuart Whitby]

use netstat to monitor all sockets, or lsof -i or -U if you want to see things at a process level (or simply lsof | grep LISTEN or ESTAB).

For ndd, I generally get full system info using:

for i in $( ndd -get /dev/tcp ? | awk '{ print $1 }' )
do
echo $i
ndd -get /dev/tcp $i
done

Some of this will come back with error, but otherwise it will give you full tcp settings for the system.

[James A. Donovan]

If you want your modifications to survie a reboot, then you need to enter them in the /etc/rc.config.d/nddconf file. The file contains instructions on how it should be modified.

Also, here is a good link ( http://www.sean.de/Solaris/soltune.html ) for solid info on most tcp/ip parameters. It is Solaris specific, but most of the information is applicable to HP-UX as well.

[Bharat Katkar]

HI Vaman,
After long time .. !!!
You can use "netstat" command to monitor network status.
For sockects in particular use "netstat -a".
See man netstat for more details.

For viewing TCP parameters use:
# ndd -get /dev/tcp
For setting the same use
# ndd -set /dev/tcp

See man ndd and man nddconf.

Hope that helps.
Regards,