How can I modify the system's UDP socket receive buffer ?

[Frank Li]

Hi,

Does anybody know how to modify HPUX11.0 's UDP socket receive buffer ? It seems you can't modify it in SAM .

When I use a small C program to get the default socket buffer size , it seems too small .
******************************************************
SO_RCVBUF: default = 32768
SO_SNDBUF: default = 32768
******************************************************
How can make it lager in the system wide ?

thanks.
Frank.

[Terja]

Now all the networking paramters are controlled by a command called NDD
type in

ndd -h supported to get a list of all the parameters you can change.
To keep it system wide and each time you restart, edit the nddconf file under /etc/rc.config.d.
Hope it helps

Terja

[Brian Hackley]

Frank,

man setsockopt() tells you how your program can set SO_SNDBUF SO_RCVBUF for TCP and UDP.
man tcp(7) and udp(7) discuss the HPUX defaults.

Systemwide default can be changed with ndd, tcp_send => tcp_xmit_hiwater_def & tcp_receive => tcp_recv_hiwater_def
I have heard of a hidden tunable for udp_recv_hiwater_max, but have not tried it.
Once you've determined the ndd does what you want, edit /etc/rc.config.d/nddconf to make the change take effect upon future reboots.

Hope this helps,

-> Brian Hackley