It should be possible to do the mount with this NetBSD command:
  ssh> mount -o-2 192.168.1.1:/netbsd /mnt
The mount option -o-2 says "Use NFS v2"

The /bin/rcmd problem is a bug that needs to be fixed.
(That program is missing in the ramdisk root's rd_bin.)
Mind sending a PR for that?

bingm@stream.csis.gvsu.edu writes:
 > Hello, 
 > 
 > I inherited a Sun 3/80 (8MB, 2 100 SCSI drives, mono monitor) from
 > school without an OS, so I'm attempting to install NetBSD 1.4.
 > 
 > I grabbed the 1.4 sun3 package (with sun3x integrated). I'm 
 > booting from the network with a Redhat 6.0 box on the same
 > network. RARP assignes the IP, bootparamd gives the parameters,
 > and it executes the netboot program. 
 > 
 > 3/80(chaos): 192.168.1.4
 > Redhat: 192.168.1.1
 > 	
 > Here's /etc/bootparams:
 > 
 > chaos root=192.168.1.1:/netbsd gateway=192.168.1.1:0xffffff00
 > 
 > The machine boots /netbsd/netbsd-ramdisk3x and I get to ssh just
 > fine, but here's the problem:
 > 
 > ssh> ifconfig le0 inet 192.168.1.4 up
 > ssh> mount 192.168.1.1:/netbsd/mnt
 > ssh> cd /mnt
 > ssh> dd if=./miniroot of=/dev/rsd0b
 > dd: file too big
 > ssh> cat miniroot
 > cat: file too big
 > 
 > I originally tried the knfsd from linux 2.2.9, which uses NFSv2, but
 > netbsd-ramdisk3x only speaks NFSv3. So, I tried linux 2.2.5 with 
 > NFSv3 support and I keep getting the "file too big" error message
 > with every read() call. I assume this is because of the alpha state
 > of the linux NFSv3 server.
 > 
 > tftp and rsh would be viable options for copying the miniroot, but
 > tftp is not located on the ramdisk, and rsh does this:
 > 
 > ssh> run -bg dd if=/dev/pipe of=/dev/rsd0b obs=8k
 > ssh> run -o /dev/pipe rsh 192.168.1.1 cat /netbsd/miniroot
 > rsh: Cannot execute /bin/rcmd
 > 
 > I've used both the stock NetBSD 1.4 sun3x and the 19990518
 > snapshot.
 > 
 > I'm running through a dialup, so I don't have practical access to 
 > another machine with a NFSv3 server. 
 > 
 > Any help would be greatly appreciated.
 > 
 > -matt
 > 
 > -- 
 > http://www.csis.gvsu.edu/matt
 > http://contempt.csis.gvsu.edu
 > 16 F7 69 A2 78 AC 83 7E AD 04 BE 82 90 B0 47 58
 > Try to understand everything, but believe nothing
 >