[Babel-users] How to properly add an unreachable route?

[Dave Taht]

On Sat, Jul 12, 2014 at 4:53 PM, Juliusz Chroboczek
<jch at pps.univ-paris-diderot.fr> wrote:
>> 1) Does this also export the default route? (not what I want by default)
>>
>> redistribute ip 0.0.0.0/0 le 24 allow
>> redistribute local deny
>
> Depends on how the DHCP server is installing the route.  If it's using the
> "boot" protocol, as it should, Babel will ignore it by default.  In any
> case, you can force ignoring the default route by adding the following
> *before* the allow:

Openwrt at least, installs it static, not boot.
I will look into what it will take to stop doing that.

>   redistribute ip 0.0.0.0/0 le 0 deny
>
>> 2) Will this correctly export the default route if I changed it to
>> allow? If a box isn't a default gateway should I put in a specific
>> deny or allow line? Or use eq as I just did? or?
>>
>> redistribute ip 0.0.0.0/0 eq 0 deny
>> redistribute ip 0.0.0.0/0 le 24 allow
>> redistribute local deny
>
> No.  If the DHCP server is doing its job properly, it's marking its routes
> with the protocol "boot", which is a hint to proper routing protocols to
> ignore the route.
>
> Redistributing a DHCP route over a roting protocol is not robust network
> design -- DHCP should be announcing routes derived from a routing protocol,
> not the other way around.  However, support for redistributing in the DHCP
> to Babel direction was grudgingly added after enough users asked for the
> feature (yeah, I know, I'm weak):
>
>   redistribute ip 0.0.0.0/0 le 0 proto 3 allow

The core case here is on a default gateway connected to the internet,
which is rather a common one.

> (When you don't mention a proto number, the redistribution is taken to
> apply to all proto numbers except 3.)

I get it.

> -- Juliusz



-- 
Dave Täht

NSFW: https://w2.eff.org/Censorship/Internet_censorship_bills/russell_0296_indecent.article