At the recommendation of sever people, I intend to set up an old 
Sparc IPX with two ethernet interfaces as a NAT router and firewall
using NetBSD.

Several days ago, just to familiarize myself with NetBSD, I completed 
the installation of v 1.5.1 on a Sparc IPC.

I am now trying to get the IPC connected to my home LAN which consists 
of about 10 miscellaneous machines running Redhat Linux on both Sparc 
and Intel platforms, Solaris on a Sparc platform, and several Windows95
boxes of various flavors.  They are all behind a NAT server which is 
running NAT32 software on an Win95 Pentium-90 and is set up to use 
static addresses on the LAN side.  This arrangement has been in place 
for a couple of years and has been very, very stable with no problems 
configuring any of the various OS to use the 172.16.x.x LAN and the 
172.16.2.100 machine as the gateway.

Now I have NetBSD set up and have it working and able to ping machines 
both on the LAN and outside -- for a while.  After some period of time, 
say 30 minutes or so, I can no longer ping anything outside (even 
by numeric IP) and the problem is solved only when I stop and restart 
the NAT software on the gateway machine.

I also notice that NetBSD sets itself up with IPv6 enabled and when 
I do >route show, I am able to get a IP routing table with everything 
looking OK followed by an IPv6 routing table which I do not fully 
understand.  When the NetBSD machine ceases to communicate through 
the gateway machine, this >route show command hangs after displaying 
just the IP routing table and the headings for the IPv6 portion.  It 
takes a ^C to get out of it.  Similarly, when this happens, >ping
xxx.xxx.xxx.xxx hangs when attempting an outside IP but works fine 
with the IPs of other machines in the LAN -- including working fine 
pinging the 172.16.2.100 machine which is supposed to be the gateway.

I do not get a "no route to host" message when this problem occurs.
Ping just hangs and requires a ^C.  (If I delete the gateway from 
the routing table, ping returns the expected "no route to host" 
message.)

I suspect that NetBSD is attempting some automated route discovery 
or some such and that is this is hanging its ability to deal with 
the NAT machine as gateway until the NAT software is stopped and 
restarted.  The problem well may be in the NAT software, but NetBSD 
is the only OS which is having this issue.

Meanwhile, other machines on the LAN have no problem in continuing 
to use the NAT machine gateway, even when the Sparc NetBSD machine 
can't.  And other machines on the LAN can ping the Sparc at its 
IP of 172.16.2.114.

What's going on here?  I can provide the results of >route show 
and >ifconfig le0, etc. if that would help in diagnosing this 
problem.

Thanks.

Will
The Old Bear