HP-UX 11i December 2002 Release Notes

Internet and Networking Services
Network Transport
Chapter 12
243
Beginning at HP-UX 11i, netstat -I <interface> displays statistics accumulated
since the last system reboot. This matches netstat -I output for HP-UX releases 10.20
and earlier.
Compatibility Issues
There could be some compatibility problems with scripts where they look for the “Use”
field.
Virtual IP (VIP) Address for the System
Using the loopback interface lo0:1, lo0:2, and so on, the system will respond to the IP
address assigned to these interfaces using any physical interface. Thus, a system can
now have a “systemIP” address that will be available as long as one interface stays
usable.
In some configurations, a system needs to keep a “well known” IP address that will
always be available even if an interface goes down. With the new VIP feature, a remote
user can specify an IP address that will respond regardless of the local interface from
which the packet arrived. This feature is an enhancement.
setsockopt()
If you determine that certain applications always ask for the largest socket buffer
allowed, then you may want to set these variables and limit the amount of memory used
by such applications. (When an application opens enough of these large sockets and the
system does not contain a lot of memory, then the system may starve for memory if the
application quits reading from the socket.)
The system-wide kernel parameters, tcp_recv_hiwater_max (for TCP sockets) and
udp_recv_hiwater_max (for UDP sockets), now limit the maximum buffer sizes
specified in the SO_SNDBUF or SO_RCVBUF setsockopt() parameters.
Applications that request sockets with send or receive buffers larger than high-water
marks set by the administrator will fail. In other words, a setsockopt() call with a
SO_SNDBUF or SO_RCVBUF option that exceeds the corresponding kernel parameter value
will fail, returning the errno value EINVAL.
T_OPTMGMT
If you determine that certain applications always ask for the largest buffer or transport
service data unit (tsdu) allowed, then you may want to set these variables and limit the
amount of memory used by such applications. (When an application opens enough of
these large sockets and the system does not contain a lot of memory, then the system
may starve for memory if the application quits reading from the endpoint.)
The kernel parameters tcp_recv_hiwater_max (for TCP sockets, default 2GB) and
udp_recv_hiwater_max (for UDP sockets, default 2GB) now limit the XTI_RCVBUF
parameter maximum buffer size. The kernel parameter tcp_xmit_hiwater_max (default
2GB) now limits the XTI_SNDBUF parameter’s maximum buffer size.
Applications that request sockets with buffers or tsdus larger than high-water marks
set by you will fail. In other words, a t_optmgmt() call with a tdsu or etsdu option that
exceeds the corresponding kernel parameter value will fail with TBADOPT.