Advertise a subnet without an interface over OSPF on FTD

[Nikolaos Milas]

Hello,

I am on FTD2130.

I have configured various interfaces with their respective subnets and they are advertised successfully over OSPF.

I want to advertise over OSPF a subnet which includes public addresses to be used as NAT gateways (for various private networks).

I know that in OSPF the network command does not directly specify the network that should be advertised to other routers. Instead, it defines a range of addresses, and if any interface's own IP address falls into that range, the protocol will advertise the whole network of that interface as-is.

How can I configure OSPF on FTD to advertise this particular subnet - which is NOT associated with any interface - so that all network knows that this subnet is "parked" on the FTD device?

Thanks,
Nick

[MHM Cisco World]

This subnet use in which interface' let assume ourside 

Use 

Staitc route to outside interface and then redistrubte this static into ospf

MHM

[Nikolaos Milas]

Thanks for your prompt reply.

I would like to ask: What do I use as a gateway? The "outside" interface IP Address on FTD is not accepted as a gateway. "outside" is also selected in "Interface" field.

Instead of configuring a "particular" interface (during static route configuration), should I configure it as a "Null0" interface (which does not require a gateway)? It seems to be working like that.

Thanks,
Nick

[MHM Cisco World · Accepted solution]

try use Null0 if you see drop then use ISP IP as GW.

MHM

[Nikolaos Milas]

I confirmed it works fine with Null0.

Thanks a lot.

Cheers,
Niick