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nsumner36
nsumner36
New Member
November 15, 2020
Question

Multiple VLANs between 3 sites

  • November 15, 2020
  • 1 reply
  • 2352 views

I have 3 office with a number of different VLANs to make life simple lets say the following

 

Office A

VLAN 191

192.168.1.0/24

VLAN 10

10.10.10.0/24

 

Office B

VLAN 192

192.168.2.0/24

10.10.11.0/24

 

Office C

VLAN 193

192.168.3.0/24

10.10.12.0/24

 

All offices are directly linked with layer-2 500M links from the local telco. (IE Office A-B, Office A-C, and Office B-C). Forming a triangle as it were.

 

If I have the same VLAN in multiple offices than I get a loop (the 10 network which is for phones used to be one streched VLAN) but of course the loop takes you down, so it didn't cover all 3 lines.

 

All Internet goes through Office A. I currently have a link between all offices and then route all VLANs over that link. But the end result of course is that everything becomes a giant mess. All routing is done using OSPF which works rather nicely.

 

But I don't see how I can easy keep VLAN 192.168.x.x separate from the 10.10.x.x VLANs. I really want the "DATA" vlan 192 to be able to talk, and the VOICE vlans 10 to be able to talk, but very limited communication between them. But they both ultimately must connect between all offices and even out to the internet.

    1 reply

    sw2090
    SuperUser
    sw2090
    SuperUser
    December 10, 2020

    looks rather easy as there is no overlaps ;)

    Just create static routes for the vlans on the fortigates so traffic can be routed between the vlans of the offices.

    Then create the policies to allow the traffic you want to allow.

     

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