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Allocated smaller subnet to another router

Posted: Sun Aug 26, 2018 5:03 pm
by isp85
Hi,

I've one mikrotik router that announcing a /23 IP network to our upstream provider, now I want to allocate half those IPs to another internal mikrotik router so their users can use those IPs too.
How do I achieve this?
Thanks :)

Re: Allocated smaller subnet to another router

Posted: Sun Aug 26, 2018 5:29 pm
by Vooray
Announce part of network at your second router. Just keep in mind, that some AS can filter out prefixes longer then /24

Re: Allocated smaller subnet to another router

Posted: Sun Aug 26, 2018 7:34 pm
by isp85
Thanks but how?

Re: Allocated smaller subnet to another router

Posted: Sun Aug 26, 2018 7:48 pm
by Vooray
First router announce 20.0.0.0/23. Second router announce 20.0.1.0/24.
Or first announce 20.0.0.0/24, second announce 20.0.1.0/24.

Re: Allocated smaller subnet to another router

Posted: Sun Aug 26, 2018 8:24 pm
by isp85
First router announce 20.0.0.0/23. Second router announce 20.0.1.0/24.
Or first announce 20.0.0.0/24, second announce 20.0.1.0/24.
I've only one IP that can connect to our upstream and announce /23 block. now in order to announce 20.0.1.0/24 can I do it through the first router?

Re: Allocated smaller subnet to another router

Posted: Sun Aug 26, 2018 8:47 pm
by Vooray
Of course you can, but it does not have much sence. You already announce your /23 to the world.
You can stick /24 to another router in your intranet.

Re: Allocated smaller subnet to another router

Posted: Sun Aug 26, 2018 9:40 pm
by isp85
Of course you can, but it does not have much sence. You already announce your /23 to the world.
You can stick /24 to another router in your intranet.
can you give me config as an example? I'm kinda new in this BGP section.

Thanks again

Re: Allocated smaller subnet to another router

Posted: Sun Aug 26, 2018 10:51 pm
by Vooray