[nos-bbs] JNOS routing to TUN0

Mark Phillips g7ltt at g7ltt.com
Sat May 16 12:24:44 EDT 2009

Did you publish your arp?

On the Linux box you have to get it to respond to calls addressed to
your JNOS virtual box.

What will then happen is that when calls from your JNOS box to your lan
go out the lan device will ask for the hardware address of the JNOS box.
You linux box will offer up its own address and thus the packet flows.

On Sat, 2009-05-16 at 08:21 -0700, Bill V WA7NWP wrote:
> Good morning...
> Sun's out in Seattle, it's warm, the lawn and the weeds are growing
> like crazy -- so it's obviously a good day to stay in and do some JNOS
> work.
> I'm setting up my first TUN interface.   The point-to-point connection
> between the host linux system and JNOS2.0f is working fine.  At least
> the PING is working.
> I've used Maiko's basic setup as a start:
> ---
> autoexec.nos:
>   ip address
>   attach tun tun0 1500 0
>   ifconfig tun0 ipaddress
>   ifconfig tun0 netmask
>   ifconfig tun0 mtu 1500
>   pause 1
>   shell ifconfig tun0 pointtopoint mtu 1500 up
> ----
> The LAN address for the linux host is
> The JNOS instance is
> The netmask on tun0 implies that interface should be able to contact
> any station on the 192.168.27 LAN..
> Sending a ping to  -- the windows box running the BPQ32
> node -- shows an outgoing ICMP Echo Request on tun0 as expected.
> No reply.   Likewise on the windows box, a ping to
> (JNOS) doesn't appear on TUN0.
> In the old SLattach setup, I'd have hard coded a proxy ARP and route
> statement on Linux so it would look for the JNOS packets and forward
> them.  I'd also have to enable IP forwarding in the /proc system.
> This leads to the primary query of this posting - Is the proxy ARP and
> IP forwarding still necessary with TUN or is there another mechanism?
> Once I get IP working between JNOS and other LAN systems, I'm assuming
> it's a simple matter of adding the route default entries to open up
> the network connectivity.
> Thanks and 73...
> Bill - WA7NWP
> PS.  I'm not really going to stay inside today.    The rain comes back
> Monday so there's lots to be done before then.
> PPS.   A sunny weekend and rainy work week is just plain scary...
> Normally it's the other way.
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Mark Phillips, G7LTT/NI2O
Randolph, NJ

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