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Infotech22
Explorer III
November 28, 2023
Solved

Segmenting our Network

  • November 28, 2023
  • 12 replies
  • 7819 views

Hello to all Cybersecurity enthusiastic,

I would like to get some best practices, advices for my next project.

On one location we didn't do barely any segmentation since last IT Manager so it's time to make it more secure and better.

Current Situation is like this:

  • VLAN 1 "Clients"
    • Here in our Clients VLAN we have regular clients (notebooks, workstations), printers, VoIP devices, meeting devices (cameras, microphones etc)
  • VLAN 2 "Servers"
    • Here in Servers VLAN we have domain controllers, file servers, backup servers, repositories etc

What would be a general recommendation?
I would like to segment it a bit more and create separate VLANs for Printers, VoIP, IoT, Backup Network etc.

Our Infrastructure is as follows:
2 x FortiGate 200F in an HA Cluster (Active/Passive)
2 x Core FortiSwitches in an MC-LAG
3 X Access FortiSwitches

 

I'm new to this forum.
I'm NSE4 certified. 

Best answer by ndumaj

Hello Infotech22,

You can add additional VLANs on the interfaces in order to segment your network.
Please review the following article:
https://community.fortinet.com/t5/FortiGate/Technical-Tip-How-to-create-a-VLAN-tagged-interface-802-1q-on-a/ta-p/193893

- Then firewall policies should be created to allow traffic from the switch interface to the interface or the VLAN to reach. NAT should be enabled were it is needed.

-BR-

12 replies

ndumaj
Staff
ndumajAnswer
Staff
November 28, 2023

Hello Infotech22,

You can add additional VLANs on the interfaces in order to segment your network.
Please review the following article:
https://community.fortinet.com/t5/FortiGate/Technical-Tip-How-to-create-a-VLAN-tagged-interface-802-1q-on-a/ta-p/193893

- Then firewall policies should be created to allow traffic from the switch interface to the interface or the VLAN to reach. NAT should be enabled were it is needed.

-BR-

Infotech22
Explorer III
November 28, 2023

Thank you for the suggestion.

Yes, the plan is to do something like that

VLAN 1 is 10.10.0.0/16
VLAN 2 is 192.168.10.0/24

So I would probably do some subnetting on the VLAN 1 so that I create different Subnets for more VLANS, example:
10.10.1.0 - 10.10.5.0 - for Clients

10.10.255.0 - 10.10.255.254 - For Pritners etc.

Is this approach okay?

_emeste
Visitor III
November 28, 2023

Hi,

In my opinion, network segmentation is a process that requires good planning.
I always trying to approach this issue in the following way
1. I'm trying to determine which VLANs I should create and then I group the devices. For example:
Printers
Clients
Media
WiFi
DCs
etc.
Imo An inventory of the network is necessary.
2. I'm creating a network diagram at a logical level.
3. I'm preparing the device configuration and move the devices into predetermined VLANs.

If devices are in defined VLANs you can focus on the security layer. Limit access to each network segment to only those who need on Your firewall

Also The ZTNA concept can be useful in planning network segmentation.

ps.

In the case of VOIP, it is worth noting that users often have their PCs connected to them.

Infotech22
Explorer III
November 28, 2023

Thank you for the informations.
I have 2 month to plan everything so each recommendations is welcomed. 

ndumaj
Staff
Staff
November 28, 2023

Hello,

If you have VLAN 1 is 10.10.0.0/16 that cover

10.10.0.0 - 10.10.255.255 

You cant create a new vlanx 10.10.1.0 - 10.10.5.0 - for Clients or 10.10.255.0 - 10.10.255.254 - For Pritners etc.
The new vlans should be on different subnet :|

You can also review the following articles that might help to make the changes:
https://community.fortinet.com/t5/FortiGate/Technical-Tip-Transfer-Migrate-VLAN-to-another-interface/ta-p/245731
https://community.fortinet.com/t5/FortiGate/Technical-Tip-Edit-VLAN-ID-of-a-VLAN-interface/ta-p/215295

-BR-

Infotech22
Explorer III
November 28, 2023

Yes,

That is the current situation of the VLAN 1.

I will subnet it to have smaller number of available host per vlan.
For Clients I dont need more than /24 but in this case i would use something like
10.10.0.0/21 etc.

So that I have rest to divide for Printers, IoT etc

I hope that you understand what I'm trying to say 

ndumaj
Staff
Staff
November 28, 2023

As Emeste mentioned network segmentation is the most important process that requires good planning, if you have a good segmentation plan then the implementation the easy part.

Yeap  you can divide VLAN1 10.10.0.0/16 into smaller vlans for clients:
10.10.1.0 - 10.10.5.0 - for Clients --> 10.10.0.0/21
For printers:
10.10.255.0 - 10.10.255.254 - For Printers -->10.10.255.0/24
etc..

that works :)
-BR-

Infotech22
Explorer III
November 28, 2023

One more question for all of you :)
If I have VLANs with different subnets,
Examples:

  • Clinets: 10.10.0.1 /23
  • Printers: 10.10.255.1/24

Our Forti Infrastructure is MCLAG, does this means that traffic for clients to printers will go first to FortiGate then back to FortiSwitchse since this is Routing between subnets?

ndumaj
Staff
Staff
November 29, 2023

Hello,
As far the SW are managed by FGT is the FGT that will manage the traffic and routing part.
If you run a sniffer or PCAP on FGT GUI you will see traffic how it is going on FGT.
-BR-