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AlexM2020
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/30 with OSPF Network

Sun Sep 12, 2021 11:06 am

Good morning,
I have a situation that I cannot resolve.
I have an OSPF network which essentially works fine and I interconnect all my PPPoE routers. Each PPPoE router delivers addresses in 10.0.0.0/22 boxes. To allow internet access, it establishes an EOIP with the head router where it obtains a Public IP. The request is as follows, how can I assign a / 30 to a client? I have made several attempts but have not yet found a configuration that works. Before the OSPF network I had a bridge network and I had no problems there, I configured two crossed routes and everything was perfect. Could anyone help me in this situation? thank you in advance.
 
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krafg
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Re: /30 with OSPF Network

Sun Sep 12, 2021 2:36 pm

Use a VLSM calculator if you not know how to calculate it.

Regards.
 
millenium7
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Re: /30 with OSPF Network

Mon Sep 13, 2021 5:27 am

If I understand correctly, you want to assign both a private IP i.e. 10.0.0.6, as well as additional IP addresses?
You can assign additional IP's with additional RADIUS options. It depends if your system supports this or not (Splynx for instance does, you can assign as many IP addresses to a single PPPoE connection as you want, it doesn't have to be a /30)

There is also a better/easier method, you can directly assign /32 addresses. You don't need them to be in a broadcast domain
I.e. its totally valid to have the customer receive 1.2.3.4 and the default gateway as 5.6.7.8 (your router)
You can completely skip the private IP part
However you can also then assign 2.3.4.5 and 3.4.5.6 to them as additional IP's if you wish
 
AlexM2020
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Re: /30 with OSPF Network

Mon Sep 13, 2021 12:43 pm

Sorry but most likely I misstated the configuration.
I have a public / 24 subnet. I have a head router where I have configured a / 25 of my public subnet in order to have a remainder to assign the / 30 to the customers who request it.
Then I set up an all ospf network with private addresses.
To allow the use of public IPs, each router establishes an eoip towards the head router.
Everything works perfectly. The problem arises when I want to certify a / 30 to a customer.
When I had a bridge configuration I simply made a route xxx.xxx.xxx.xxx/30 to Client IP and vice versa on the client's router. Right now I don't know how I could set up the routes as it goes through more than one router.
Would you have some documentation to send me for reference or some other kind of help would be appreciated.
I insert a short diagram to explain this graphically.

Internet -- xxx.xxx.xxx.xxx/24 -- Router 1 -- 172.16.1.0/30 -- Router 2 -- 10.0.0.0/22 -- Client
 
millenium7
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Re: /30 with OSPF Network

Mon Sep 13, 2021 1:35 pm

Are you assigning /30 to customers because you want to give them 4 public IP addresses? Or because you want to assign them just 1 public IP address and you are using the other 3 as network/broadcast/gateway addresses? i.e. wasting 3
Because if you are doing the latter, you don't need to. You are just wasting 75% of your public address space, you can literally assign all 256 addresses (yes including .0 and .255) individually to customers

I want to be sure of that first because if you are doing the latter, lets look at adjusting your setup so you aren't wasting address space. Because you don't actually need EoIP tunnels either (its just wasting bandwidth via extra overhead)

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