A ping question and the infamous "sendto: No buffer space available" message

[John Robert LoVerso]

In article <4355 at helios.ee.lbl.gov> leres at helios.ee.lbl.gov (Craig Leres) writes:
> Ralph Yozzo writes:
> > Has anyone run into a situation where "ping'ing" a host gives a
> > sendto:No buffer space available
> 
> Sometimes, you can reset the
> hardware by ifconfig'ing the interface down and then back up.

This will probably only work in 4.3tahoe and later, where a call to
if_flushq() was added to if_down().  This just frees all the packet
chains queued for the interface - without this, ifconfig'ing back up
just leaves the i/f queue full.

Some useful information can be gleamed with the "ifnet" adb script
(in /usr/lib/adb), which will show you (among other things) the size
of the i/f queue.  This should work on any reasonable machine providing
a /dev/kmem.  On an Annex, "netstat -iQ" gives the queue size.

John