Here's one for the FAQ...

A co-worker was configuring a NetBSD system to act as a Jumpstart server
for many Sun Netra servers.  He was running into a problem that looked
very much like an NFS interoperability issue -- that is, the client would
get partway through initialization, then fail to mount the file system
that contained the Solaris distribution.

There was much combing through tcpdump output, scratching of heads, and
far too much anxiety for thorpej.

Well, it turns out that Solaris (2.7, at least) sends an ICMP MASK REQUEST
to the network the server is attached to in order to determine the netmask,
since Sun, in their great wisdom, has yet to fully embrace the wonder that
is DHCP.  Well, if the client doesn't get a reply to this ICMP message, then
it stops dead in its tracks.

So, if you ever have the occasion to configure a NetBSD machine as a
Jumpstart server, make sure to set net.inet.icmp.maskrepl = 1.

-- 
        -- Jason R. Thorpe <thorpej@zembu.com>