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astuke
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Joined: Mon Jun 30, 2008 11:02 pm

OSPF Config

Thu Oct 29, 2020 7:27 pm

diag.jpg
I'm trying to Get OSPF to work between 19 + sites.
I can make everything work with static routes, but OFSP will not work.
If I configure Site A with OSPF, Neighbors will list in the router, however they do not list in Site C for instance.
Site A and Site B have servers in them so all sites talk to these two over GRE tunnels.
Site C is going to be a backup connection for if Site A is down.
I would like to have routes move through Site A to Site C from all of the clients, but I would like them to move through Site B to Site C if Site A is down.
Another issue we run into is that sometimes one tunnel go down, I would like for this connection to traverse another path if that happens.
Or would it be better to setup a Tunnel between all sites? I would like to use OSBF and not Static.
Does anyone know why this configuration would not work? Is there a limitation between GRE and OSPF, or am I just doing it completely wrong in the first place?
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tdw
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Re: OSPF Config

Thu Oct 29, 2020 7:53 pm

That should work, we have a site with something similar for six Mikrotiks although using L2TP/IPsec and /32 addresses for the interlinks, so it will be a configuration issue.
 
kd2pm2
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Re: OSPF Config

Fri Oct 30, 2020 1:47 am

In order for OSPF to work (and I suspect you already know this)....all sites have to be in the same OSPF area and you need to assign the networks so it can figure out which interfaces have which networks, or you could just do the interfaces directly with what networks they have on them. Make sure that none of them show /32 and that they reflect the proper cidr.

When I was adding OSPF to my network, I neglected to put the proper cidr in and the router assumed /32 and nothing was working. Once I went in and changed my networks to /30, everything immediately came up.
 
astuke
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Re: OSPF Config

Fri Oct 30, 2020 4:19 pm

Are you talking about the loopback addresses? The only thing I have on /32 is the loopback.
 
kd2pm2
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Re: OSPF Config

Fri Oct 30, 2020 4:24 pm

When I originally was putting in the networks, I mistakenly did not put the cidr in there and ROS assumed /32 and nothing would work. I went back to the networks and edited them to be /30 and then ROS know what to do

So the thought is that your OSPF networks that you added should show that they are indeed /30 and not /32. The example below shows what your networks should look like when you do a print.

Flags: X - disabled, I - invalid
# NETWORK AREA
0 172.16.0.0/30 backbone
1 192.168.88.0/24 backbone
 
astuke
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Re: OSPF Config

Fri Oct 30, 2020 4:40 pm

I had that correct, I wasn't sure what i should put under networks in siteA and Site B
 
kd2pm2
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Re: OSPF Config

Sat Oct 31, 2020 2:03 am

Sites "A" and "B" should have 5 networks in their OSPF tables. The internet, LAN and the 3 inter-network ones.

Sites "C" and "D" should have the 3 networks that connect to those. The 2 inter-network and the LAN

Sites A and B should advertise their external internet connection to everyone else.
 
astuke
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Re: OSPF Config

Thu Nov 05, 2020 11:22 pm

I had a default rule in both routers
9 X ;;; defconf: drop all not coming from LAN
chain=input action=drop in-interface-list=!LAN log=no log-prefix=""
I disabled this, and it started connecting... However, now the routes are going in and out of the routing table. I tried disabling all of the firewall rules, but it produced the same effect.
I'll have routes for a sec, then gone, then back again, then gone.
 
astuke
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Re: OSPF Config

Thu Nov 05, 2020 11:24 pm

Sorry, I should clarify, I've taken 4 routers out of the loop and just trying to get two working together over GRE and OSPF, so basically dropped C and D for now.
 
astuke
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Re: OSPF Config

Fri Nov 06, 2020 12:03 am

I figured out my flapping issue, turns out I had some routes set to redistribute in my ospf instance.

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