In the following output, why does vpn1 route/ping to instead of to is network gateway with no nat. is dual home host with nat enabled.

root@vpn1:~# ip ro via dev eth0  src dev eth0  proto kernel  scope link  src
default via dev eth0  metric 100

root@vpn1:~# traceroute

traceroute to (, 30 hops max, 60 byte packets
 1 (  0.287 ms  0.257 ms  0.317 ms
 2  * * *
 3  * * *
 4  * * *
 5  * * *
 6  * * *
 7  * * *
 8  * * *
 9  * * *
10  * * *
11  * * *
12  * *^C

root@vpn1:~# ping

PING ( 56(84) bytes of data.
64 bytes from icmp_req=1 ttl=127 time=0.321 ms

--- ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.321/0.321/0.321/0.000 ms</br>

On the other side, has a following configuration

boban@boban-desktop:~$ ip ro dev ppp0  proto kernel  scope link  src  
x.y.z.q/28 dev eth0  proto kernel  scope link  src x.y.z.56  metric 1  
** dev ppp0  scope link**    
default via x.y.z.62 dev eth0  proto static  

So, network is on ppp0 interface, vpn (maybe this is of bigger importance than I think).

boban@boban-desktop:~$ sudo iptables -t nat -S  
boban@boban-desktop:~$ sudo iptables  -S  

Difficult to tell without seeing more. What is the default route configuration at Could you get a tcpdump of the traffic on the wire?

I'd suspect an ICMP redirect from telling your host to use instead.

  • where is your VPN gateway then? could you add its addresses, routing configuration and information about the implementation (mainly if it is bridging or doing proxy arp) as well please? And a tcpdump would still help a lot. – the-wabbit May 31 '11 at 9:40
  • I'm starting to think that it's not the routing problem here. I've tried to connect to ppp from windows, and I've got client address, server address From vpn1, I can ping, but not So I can't route to as I should. – Boban P. May 31 '11 at 11:32
  • How to solve it? – Boban P. May 31 '11 at 11:33
  • I don't know details since it's remote vpn server which is not set up by me. All I have it is login credentials and server IP. Which exactly tcpdump are you are interested? – Boban P. May 31 '11 at 11:58
  • I still don't quite get it - you have a host at with a route to through a PPP VPN interface, right? This route includes the network, which the host itself appears to be in locally - right? In the same network you have vpn1, but it can only reach through a PPP (VPN) connection through the gateway - correct? It would help to have some kind of conceptual drawing of what is where. And a tcpdump -vne off the station you are trying the ping from - i.e. vpn1. Feel free to just update the question with this information. – the-wabbit May 31 '11 at 12:44

I would expect to see a subnet mask for that route - the fact that I don't see one seems to indicate that it isn't doing the right thing.

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