Non-local IP for next hop in routing

Asked Oct 22 '14 at 17:54

Active Oct 23 '14 at 15:59

Viewed 359 times

I'm working with an MPLS network and I am slightly confused about some route entries.

Interfaces are (these are fake IPs):

eth0 10.10.10.1/24 (LAN)
eth1 10.9.9.1/24 (MPLS)
eht2 2.2.2.2/24 (Public)

There are a series of normal entries, such as:

Net: 10.1.0.0/24 Nexthop: 10.10.10.5
Net: 10.100.0.0/23 Nexthop 10.10.10.5 (these obviously go over eth0, but it is not specified)

The routes I can't figure out look like this:

Net: 10.166.0.0/24 Nexthop: 10.166.0.9 Interface: eth1
Net: 10.167.0.0/24 Nexthop: 10.167.0.9 Interface: eth1

These are weird because the next hop is not local. I'm guessing because of the Interface specified, that it places it on the wire and then arps for the next hop, but it does feel a bit strange. Is this correct, or am I missing something? Can anyone explain the mechanism here. I've been searching Google for hours, but it's hard to find the right keywords.

Thanks!

edited Oct 23 '14 at 15:59

asked Oct 22 '14 at 17:54

Eric

what is the netmask of the "MPLS" interface? – the-wabbit Oct 22 '14 at 18:35
And by MPLS, you mean an isolated routed network provided by an MPLS-capable carrier? And is one of the 'normal entries' a default route? – cpt_fink Oct 23 '14 at 04:56
We might be able to help you understand this if you listed the make/model/version of the router and it's OS. – mfinni Oct 23 '14 at 16:40
It's currently on a SonicWall firewall, but it feels to me like the routing is just a GUI on top of IPTables. – Eric Oct 23 '14 at 19:43
I also updated the netmask, but I'm not sure they matter too much. – Eric Oct 23 '14 at 19:44

Non-local IP for next hop in routing

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