nfs error diskless

[Dima Veselov <kab00m%lich.phys.spbu.ru@localhost>]

Greetings,

I am using diskless NetBSD often (real or VMs) and sometimes I
get nfs error 65 for <root>.

It seems that NetBSD won't work when NFS server is reachable
via router and work when it is reachable directly (in the
same network).

My current setup is: two PV VMs (actually copied), located in 
different networks, but connecting to the same NFS server. 
NFS server is directly reachable to VM1 and via router for VM2.
VMs are copies and both have static dhcp leases in ISC DHCPD.
Startup argument is "root=xennet0" for both.

VM1 works perfectly, but VM2 stops at "Starting network" point. 

Tcpdump says kernel mount root and happily reading 
/sbin/init, /dev and lot of other files, but when console 
says "Starting network" all communications are stopped. I 
traced it on Dom0 via mac-address so I know there were no 
NFS, no DHCP or other packet sent after this point.

Starting network.
nfs send error 65 for 172.20.27.4:/export/nfsroot/ospf1
nfs send error 65 for 172.20.27.4:/export/nfsroot/ospf1

Only two or three error messages and then it hangs forever.

fstab contain no root FS and ifconfig.xennet0 contain only
"dhcp" option (it won't work with no ifconfig file either).

Adding "set -x" to /etc/rc.d/network did not helped.

How may I debug this issue or maybe someone have won this 
battle already?

Thanks in advance.

-- 
Sincerely yours,
Dima Veselov
Physics R&D Establishment of Saint-Petersburg University