Open Shortest Path First

_jeubank_ · ‎11-11-2005

Having a little problem with OSPF and it updating its database of other routes. I have the addresses in class b range but with a 24 bit subnet mask and when putting them in the table to advertise I put a class c wild card mask. But when it comes time to send LSA's to learn other routes and advertise its own routes it is not responding within same area that being area 0. Any suggestions to why? Maybe because of the class c wild card mask?

doliver · ‎11-11-2005

OSPF by default does not summarize at classsful boundries. It may make it easier if you post your configs.

HTH,

Dean

_jeubank_ · ‎11-11-2005

!

version 12.0

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname Philly

!

enable secret xxx

!

ip subnet-zero

!

interface Ethernet0

ip address 17x.xxx.xxx.xxx 255.255.255.0

no ip directed-broadcast

!

interface Ethernet1

ip address 17x.xxx.xxx.xx 255.255.255.0

no ip directed-broadcast

!

interface Serial0

description Philadelphia S0 = S1 Connection Buffalo

ip address 21x.xx.xx.1 255.255.255.0

no ip directed-broadcast

no ip mroute-cache

clockrate 4000000

!

interface Serial1

description Philadelphia S1 = S0 Connection Orlando

ip address 1xx.xxx.xxx.x 255.255.255.0

no ip directed-broadcast

!

router osfp 1

network 1xx.0.0.0 area 0

network 17x.xx.0.0 area 0

network 21x.xx.xx.0 area 0

!

ip classless

!

olorunloba · ‎11-11-2005

Can you do a show ip ospf interface brief to confirm that your ospf is enanled on your interfaces. Note the following

1. The wildmask in the network statement is not the subnet mask that OSPF will use to advertise the routes, it is used to determine on which interfaces the OSPF protocol will run.

2. The subnet mask of the ip address on interfaces with OSPF enabled, will be the subnet mask of the advertised routes (with summary disabled, by default)

doliver · ‎11-11-2005

I don't see that you set a wildcard mask on your ospf network statements. According to your original post, you are trying to use a /24 subnet, but your network statements fall on classful boundries. If you want to use a /24 mask, you should change your network statements to reflect that.

Currently

172.16.0.0 area 0

Change to

172.16.1.0 0.0.0.255 area 0

HTH

Dean

_jeubank_ · ‎11-11-2005

Sorry about that was doing so editing and deleted it on accident. The wild card mask is there and is 0.0.0.255 do you think even though it is no summarized i should use a class b wildcard mask 0.0.255.255?

doliver · ‎11-11-2005

You can use whatever mask is required by your network. Did you verify vaa 'show ip ospf interface' that ospf was running on the interfaces?

_jeubank_ · ‎11-11-2005

Yes there are enabled on the interfaces.

Richard Burts · ‎11-11-2005

Joseph

I have tried to read through this discussion and am slightly confused about exactly what the problem is.

There are a couple of points that have been made in this discussion that are important including:

- the wildcard mask used in the OSPF network statement is only for the purpose of finding which intefaces match the network statement. Any inteface that matches the network statement will be included into OSPF.

- you can check which interfaces have been included by using the show ip ospf interface command.

- the wildcard mask used on the OSPF network statement does not have anything to do with what mask OSPF will advertise. The mask that OSPF will advertise is the subnet mask from the ip address command on the inteface.

Bearing these in mind, can you clarify what you are asking and what (if anything) does not work?

HTH

Rick

HTH

Rick

_jeubank_ · ‎11-11-2005

Basically configuring two routers with ospf and in the same area of 0. Everything is up however none of the routes are advertising to one another.

Georg Pauwen · ‎11-11-2005

Hello,

I have read this post as well and do not want to add to the confusion, but try the following (the IP addresses are made up, yours are probably different):

interface Ethernet0

ip address 172.16.1.1 255.255.255.0

no ip directed-broadcast

!

interface Ethernet1

ip address 172.16.2.1 255.255.255.0

no ip directed-broadcast

!

interface Serial0

description Philadelphia S0 = S1 Connection Buffalo

ip address 210.100.100.1 255.255.255.0

no ip directed-broadcast

no ip mroute-cache

clockrate 4000000

!

interface Serial1

description Philadelphia S1 = S0 Connection Orlando

ip address 10.10.10.1 255.255.255.0

no ip directed-broadcast

!

router ospf 1

network 10.10.10.1 0.0.0.0 area 0

network 172.16.1.1 0.0.0.0 area 0

network 172.16.2.1 0.0.0.0 area 0

network 210.100.100.1 0.0.0.0 area 0

This configuration advertises only the exact interfaces you have configured. Do the same on the other side of the link, and see if your routes get advertised then...

Regards,

GP

olorunloba · ‎11-11-2005

If you are not seeing routes then 2 things come to my mind

1. Is the neighbour state on both side full. Sometimes, one side might not be full. Use the show ip ospf neighbors to see the state on both routers.

2. Are the routes in the OSPF database, and are they know via another means such as connected interface. If the routes are known via another lower administrative distance source, such as connected, static, or eigrp, they will not show in the routing table. They will still be in the OSPF database though. This can be verified with the show ip ospf database command.

You might want to post the show ip ospf neighbor and show ip ospf database output for further analysis.