tinc and routing

[Clark Rawlins]

I'll try that but to clear up an apparent misunderstanding:
The 192.168.9.1 machine is multi-homed with 172.16.1.1 so they
are the same machine.

I added 
IndirectData = yes
and I still get the same results.

What I had hoped would happen is that traffic from 192.168.0.0/24 
headed for 172.16.1.0/24 would be routed via the vnc device to the 
gateway specified for 172.16.1.0/24 which is 192.168.9.1 from there
the traffic would be routed to the eth2 interface which is the local
subnet on the multi-homed host 192.168.9.1 - 172.16.1.1 and from there 
to its final destination.

This doesn't seem to happen for some reason.
You said that the gateway router gets ignored by either the kernel or 
by the tinc daemon?  My understanding (which may be flawed) was that for
a gateway route the kernel receives a packet, examines it's destination,
and then compares it to the entries in the routing table.  For each entry
in the routing table it bit wise ands the destination address with the 
subnet mask for the routing entry and then if the result is equal to the
network in the routing entry it is sent to the interface and in the case of 
gateway route to the host specified as the gateway.  

Then in the case of ethernet the kernel would look up the hardware address
for
the gateway router in the arp table and if not found arp on the destination 
interface for the gateway address.

Once it has the hardware address for the gateway address it sends the packet
to the gateway address as an ethernet unicast message.

I don't know how this compares to what tinc does perhaps 
you could enlighten me?

Clark

> -----Original Message-----
> From: Gus Sliepen [mailto:guus at sliepen.eu.org]
> Sent: Friday, October 10, 2003 9:13 AM
> To: tinc-devel at nl.linux.org
> Cc: Clark Rawlins
> Subject: Re: tinc and routing
> 
> 
> On Fri, Oct 10, 2003 at 08:41:24AM -0500, Clark Rawlins wrote:
> 
> > Does tinc support gateway routing to other networks across 
> its interfaces?
> 
> In router mode (the default), no. But on the other hand, you 
> don't need
> gateway routes when running tinc in router mode, and normally gateway
> routes do work but the gateway address is ignored (either by 
> the kernel
> or by tinc).
> 
> If you explicitly want traffic from 172.16.1.0/24 to go to
> 192.168.0.0/24 via the tinc daemon on 192.168.9.1, you should add
> "IndirectData = yes" to the host config file of the tinc daemon of
> 172.168.1.0/24, otherwise tinc will send traffic from 172.168.1.0/24's
> tinc daemon directly to 192.168.0.0/24's daemon, without sending it
> first to 192.168.9.1.
> 
> > The problem I am having is that on any host in 172.16.1.0/24 if I
> > attempt to ping a host on 192.168.0.0/24 the packets get 
> dropped somewhere.
> > Traceroute shows.
> 
> You can get more information from tinc using the -d and -D options.
> 
> -- 
> Met vriendelijke groet / with kind regards,
>     Guus Sliepen <guus at sliepen.eu.org>
> 
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