Connected Route Redistribution

[mahesh18]

Hi Everyone,

Here is setup 

R1---internal router----Ospf------Cisco3750--------vlan  148-------Cisco ASA-----Internet

R2---internal router ---Ospf------Cisco 3750-------vlan  148--------Cisco ASA-----Internet 

Cisco 3750 has OSPF nei ship with R1 and R2 Routers.

IP info

Cisco 3750 interface IP connected to the ASA  192.x.x.185

ASA interface IP connected to the Cisco 3750  192.x.x.186

Routing config on Cisco 3750

ip default-gateway 192.x.x.186
ip classless
ip route 0.0.0.0 0.0.0.0 192.x.x186

OSPF

router ospf 2
router-id 10.0.24.10
log-adjacency-changes
redistribute connected metric 10 metric-type 1
redistribute static subnets
network 10.0.12.62 0.0.0.0 area 0------------------R1
network 10.0.12.66 0.0.0.0 area 0------------------R2
default-information originate metric 10 metric-type 1

I need to redistribute the subnet(192.x.x.185/27 or some specfic IPs )between Cisco Switch and ASA without causing any network issues?

As this switch is also redistributing the cisco ASA default route to the ospf domain

interface Vlan148
ip address 192.x.x.185 255.255.224

Regards

Mahesh

[mahesh18]

Hi Rick,

What I mean is to advertise that subnet in OSPF domain so the rest of network knows about it.

Purpose of this is that in future if default route moves to new network topology then users can reach that

subnet using the current topology.

Regards

Mahesh

[Richard Burts · Accepted solution]

Mahesh

Thank you for the clarification. If your objective is to advertise that subnet then the easy and direct way to do that is to configure a network statement in OSPF that matches the subnet of the interface. That way OSPF will know the subnet and advertise it. It is possible to use redistribution (either redistribute connected or redistribute static) to have OSPF advertise the subnet but this is more complex than the simple network statement.

HTH

Rick

[mahesh18]

Many Thanks Rick will use the network command.

Best regards

Mahesh

[mahesh18]

yes you are correct we are not running ospf between 3750 and ASA.

[Reza Sharifi]

Hi Mahesh,

Currently, you are generating and advertising a default route using the 3750. If possible and not too much of disruption, you may want to run OSPF between the 3750 and the firewall and have the firewall generate and advertise the default route towards the internal network.  This way you can use private IP between the firewall and the 3750 and save your public IP for something else you may need in the future.

R1---internal router----Ospf------Cisco3750--------vlan  148 (OSPF)-------Cisco ASA-----Internet

R2---internal router ---Ospf------Cisco 3750-------vlan  148 (OSPF)--------Cisco ASA-----Internet 

HTH

[Reza Sharifi]

R1---internal router----Ospf------Cisco3750--------vlan  148 OSPF-------Cisco ASA-----Internet

R2---internal router ---Ospf------Cisco 3750-------vlan  148 OSPF--------Cisco ASA-----Internet 

[mahesh18]

Many Thanks Reza will use the network command.

Best regards

Mahesh