Host: centos6 with ip and gateway

Guest two vms with ip and and gateway of that of host ie

On host packet forwarding is enabled.

from guests:


Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         UG    0      0        0 eth0      *        U     0      0        0 eth0

Question1: When google.com is pinged from guest why it shows redirect host

PING google.com ( 56(84) bytes of data.

64 bytes from bom04s01-in-f7.1e100.net ( icmp_req=1 ttl=58 time=15.5 ms

**From icmp_seq=2 Redirect Host(New nexthop:**

64 bytes from bom04s01-in-f7.1e100.net ( icmp_req=2 ttl=58 time=11.7 ms

Question2 Why Guests are not sending packets through its gateway instead through host's gateway ie

deleted arp cache from guest and pinged

after that when arp cache was checked mac address of its gateway is not updated

arp -a

? ( at 00:02:b6:42:7c:b5 [ether] on eth0
? ( at <incomplete> on eth0

if packets go through then why mac address of it didnt get updated.

even tracerout confirmed it


traceroute to (, 30 hops max, 60 byte packets

1 (  0.286 ms  0.272 ms  0.264 ms

You can't set the gateways like that. If all the machines are on the same network (physical and virtual networks are bridged) then use as a gateway for VMs, if they are on separate networks (for example using NAT) then VMs and Host should be on completely different subnetworks.

Gateway is for exiting the network!

You get redirected because you can exit the network only once and that is through your (your host) is actually a node on the network and not a gateway

  • i am trying to do NATing,for that i guess its hsould be done on Gateway machine to avoid SNAT each,in this case how can i do that. – Kevin Parker Jul 17 '13 at 9:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.