Network security via Switch firewall/ACL?

[aml]

What is the recommended best way to securely allow/deny access to a specific host on a network using a Meraki MS250 switch?

I have a site with two separate networks (Trusted network LAN A & Untrusted network LAN B), but I require to access a single host (IIS server) on the untrusted network from a small number of hosts on the trusted network.

The firewalls are not Meraki and inbound traffic is not permitted through firewall B so I am looking to secure access at the Meraki switch/port.

A very-simplified diagram is as follows:

Requirements:

There is no routing/other traffic between LAN A & LAN B

Only specific hosts on LAN A (e.g. PC A1, PC A2) can access Server LANA address, and I would like to restrict this further to specific ports (i.e. HTTP/HTTPS)

Unless specified, no other hosts (e.g PC A3) on LAN A can access the server

The server can not access any other devices on LAN A

The server has multiple NICs so one (simpler?) option is to configure a network card for each network - would i be better off configuring an ACL at the Switching level, or create a Group Policy/firewall at the network-wide level and apply that to the switch port?

Or would another option be to configure a dedicated VLAN/SVI for the server's connection to LAN A?

Appreciate any thoughts/suggestions

[alemabrahao · Accepted solution]

Edited

I see two possibilities, you can either configure ACLs directly on the Meraki MS250 switch to control traffic between LAN A and LAN B or create and apply group policies (If the Firewalls are an MX) can provide more granular control and can be applied to specific switch ports or VLANs.

Configuring ACLs - Cisco Meraki Documentation

Creating and Applying Group Policies - Cisco Meraki Documentation

[aml]

Thanks, but is there any particular reason I would chose one over the other?

[alemabrahao]

If the firewall is the default gateway IP and you create the ACLs on the switch, there will be no effect because the firewall is the one that forwards the traffic.

The same explanation applies to the switch if it is the gateway, all the traffic will be forwarded through it and not to the firewall.

When I refer to all the traffic, I mean LAN traffic, whatever goes to the internet, I believe that your firewall is the default gateway for outgoing internet.

Did you get that?

[alemabrahao]

In your case, by topology, it is understood that the firewall is the gateway for these networks.

So you need to create the rules in both firewalls of network A and B.

[PhilipDAth]

You can't apply a group policy to a switch port or a switch vlan.  But I agree about using switch ACLs.

[alemabrahao]

That's right, very well remembered, but I thought about that part taking into consideration that the Firewall could be an MX.

But I forgot to ask.

[aml]

Thanks I wasn't aware of this, so it looks like ACLs are my best option

[alemabrahao]

Oh, one question I forgot, what is the default Gateway for these networks? The firewall or the switch?

If it is the firewall, you must configure the rules on it, if it is the switch, configure the rules on it.

[aml]

Default Gateway for LAN A is the Meraki switch, DG for LAN B is the firewall

For all intents and purposes all network clients on LAN B are not aware of LAN A (apart from the server, but that would be on LAN A with the 2nd NIC connection)

[alemabrahao]

So in LAN A you need to create the ACLs on the Switch and in LAN B on the firewall.