redistribute a single host of a subnet

[LostInfidel]

Hello there.

I'm a Cisco-trained guy having to manage the branch office LAN with a stack of 6850s as a network L3 core. The branch network is relatively small and there are no routing protocols other than static routing running on top of it.

My colleagues in our central office are deploying the new WAN link to us and had installed the OA740 router as an edge device in our network. They are controlling it remotely and I have no access to its configuration. We have OSPF up and running between that OA740 and my 6850 as a way for me to announce them which of my networks should go through new WAN link.

The new link is not in production right now, we're testing it before actual deployment. For a testing purposes we've chosen a couple of hosts in our branch LAN to go through the new link, while the rest of the LAN should keep accessing the central office through the legacy channels.

On my 6850, I have a directly connected network 10.8.0.0/24 (with 10.8.0.254 as a router address on that VLAN). The test host is 10.8.0.223. So I should inject just the host route to 10.8.0.223/32 into our OSPF routing process, while NOT injecting the whole network 10.8.0.0/24.

I've tried to use redistribution and route-maps:
IP ROUTE-MAP "TO_740" SEQUENCE-NUMBER 10 ACTION PERMIT
IP ROUTE-MAP "TO_740" SEQUENCE-NUMBER 10 MATCH IP-ADDRESS 10.8.0.223/32 PERMIT

IP REDIST LOCAL INTO OSPF ROUTE-MAP "TO_740"

That's not working, because there is no local host route to 10.8.0.223 in the routing table, just the network route to 10.8.0.0/24 that does not match. OK, fine, let's create it then.

IP REDIST STATIC INTO OSPF ROUTE-MAP "TO_740"
IP STATIC-ROUTE 10.8.0.223/32 GATEWAY 10.8.0.254
WARNING: Route marked inactive.

Oops... The new static host route uses the same gateway as a connected network route already covering that host. 6850 thinks it is redundant and does not add it to a routing table, albeit still keeping the command the configuration snapshot. I've found an Alcatel KB article (https://service.esd.alcatel-lucent.com/ ... umber=5994) detailing that behaviour as "by design" with a way around (to actually ROUTE some host to other gateway on the same LAN, for example) using policy routing. That workaround does not suit me as it still does not add anything to a routing table, hence, still nothing to redistribute out of it...

Basically, I'm stuck here. I have no way to inject a route into OSPF without adding it to a routing table first, and I have no way to add an active more-specific route if it is covered with already existing less-specific one.

Is there any way around it, other than putting a Cisco router between my 6850 and OA740 to handle that? I've tested it on 7206, it does allow to add /32 host route alongside with /24 network one and indeed redistributes it correctly 8((

[one6f]

very well and clearly written respect
the way around it, putting a Alcatel router between 6850 and OA740

[LostInfidel]

We've solved our issue by placing the spare 2811 as a secondary gateway out inside the branch LAN. It holds the required static host routes and redistributes them into OSPF for 6850 and OA740 to use. Traffic for test hosts is looped around through that 2811 this way, but that does not matter much and the loop will be extinguished as soon as the link will go into production.