How to summary LAN for auto VPN ?

[dimatt]

Hello,

I have a MX appliance with a lot of small LANs which belong to the same big LAN.

In place of enable all the small LAN for the VPN, i would like to use the big LAN, but i can't choose it.

 Perhaps with a static route.

Do you have any idea ?

Thanks.

[DarrenOC]

hi @dimatt - do you have a diagram you can share of your setup or can you provide further details on what you're trying to achieve?  I'm struggling to decipher your original post.  Cheers

[dimatt]

For example 2 lan likes this:

192.168.0.0/24

192.168.1.0/24

I have to enable the 2 LAN on the VPN, but i would like to declare only one (to have a better view)

How can i summarize to 192.168.0.0/23 ?

[KarstenI]

You can point a summary route to a random internal IP and advertise this route as a summary. The drawback is that for every change, the dashboard will print a dumb warning that traffic will be routed to the most specific route.

[dimatt]

Thanks.

I was thinking of the same thing.

Did you experience it ?

[KarstenI]

What do you mean with experience? The warning? Yes, and it is so annoying. It is the same warning that you get when you have the SVIs on the internal switch and have a summarized route to that switch.

[dimatt]

Sorry, i mean, do you set it on a production environnement ?

[KarstenI]

Yes, I often had this summarized route in the past. But new setups are all configured with individual routes just because of this message. 

[dimatt]

Ok, thanks.

[Ryan_Miles]

I made a short slide deck on this topic awhile ago. Posting here for reference.

Also, the BIG DISCLAIMER - this "hack/trick" isn't suggested, recommended, nor supported. So use it if you like, but just be aware at some point behavior could change or Support might recommend you not do this.

Now for the slides

https://docs.google.com/presentation/d/1FDD0qU6stBYm1dzWejoW_0vocgyB7UjUKUPi9EB_--M/edit?usp=sharing

[PhilipDAth]

I concur with @Ryan_Miles.  I have done exactly this.

You can also use this same approach to connect MXs in different networks (such as primary and DR) to the same internal network for failover.