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Does this network setup look correct? (vlanning)

Occasional Contributor

Does this network setup look correct? (vlanning)

For simplicity say I have 1 blade enclosure with GBE2 switches, in this enclosure is 8 blades

2 of these blades are management servers
2 of these blades are for a client team 1
2 of these blades are for a client team 2
1 of these blades is for client team 3
1 of these blades is for client team 4

client team 1 and 2 for security want to be virtually isolated, they need to communicate with the management servers and the internet but be invisible to other servers

client team 3 + 4 has low security requirements and need to communicate with the management servers and can communicate with each other

This is my solution (I am very new to vlanning so hopefully this all makes sense)

On the GBE2, the management servers will be in VLAN 2
CLIENT TEAM 1 will be VLAN 4
CLIENT TEAM 2 will be VLAN 5
CLIENT TEAM 3 + 4 will be in VLAN 3

vlan tagging will be enabled on all uplink and crosslink ports

The GBE2 switches feed into a linksys managed switch (I know its linksys :( but they have been great budget switches)
On the linksys switch, I will enable vlan trunking on all the ports that connect to the GBE2 switch. This linksys switch feeds to another linksys switch. This linksys switch will also have vlan trunking enabled on the ports that are vlan trunking from the previous linksys switch.

Now from here, the linksys will have ports assigned to the specific VLANs.

These ports will connect to ports on a Cisco switch that has private vlans enabled.

The management VLAN (2) will plug into a promiscuous port (the firewall (also gateway) will be connected to a promiscuous port

The client team 3 + 4 vlan (3) will plug into a community port

The client team 1 + 2 (vlan 4+5) will each have a isolate port on the switch

now with private vlaning, promiscuous ports can communicate with isolate and community ports

community ports can communicate with promiscious ports and other community ports

isolate ports can communicate with promiscious ports but not other isolate ports or community

hopefully I am on the right path, the Cisco switch is a layer 3 switch so it can do vlan routing, but because everyone is on the same subnet it would be impossible to do so thats why I went with the private vlanning, and using standard vlanning to segment the traffic until it hit the Cisco private vlan.

Trusted Contributor

Re: Does this network setup look correct? (vlanning)

Since you have a Cisco L3 switch (capable of routing and access control) I would feed the GBE2 switches (and implicitly their associated VLANs) directly in the Cisco device, bypassing the LinkSys-es. It is possible to transfer VLAN frames formed by the GBE2s to Cisco, and have the Cisco do routing and Access Control List security - which is just what you need for the specs you mentioned (keeping some subnets from talking to other subnets, permitting some servers to respond to client requests whilst cutting other traffic not allowed by your security requirements, etc.)

For you to have a clear picture of how to configure your L2 and L3 devices, you should put on paper two kinds of requirements, in this order of importance:

1) functional requirements (what applications the clients need -from LAN or Internet-, what services need some servers from other servers, system availability for servers -power supply included-, etc.)

2) information security requirements (what clients are NOT allowed to do, what server-to-server communications must NOT take place, etc.)

Advice: don't put information security requirements before functional requirements. The most secure computer is one that is shutdown, decoupled from power supplies and communication - but ofcourse this is a completely non-functionctional system.
Occasional Contributor

Re: Does this network setup look correct? (vlanning)

Hi Dan,

Thanks for your post. I looked into the ACLs and that something I will look into implementing in the future, but because of our time frame and existing infrastructure I am looking for something with minimal configuration and infrastrucute changes. I guess my question should of more been on the line of is what I am thinking possible?

New Member

Re: Does this network setup look correct? (vlanning)

I agree with the previous reply about listing functional requirements first. I would add future possibilities (expansion, relocation) to that list also. Splitting the same layer 3 network into separate layer 2 networks is generally the opposite of what you want to do. In my own IT work I have frequently come across situations where unplanned for relocation of business functions (facility change) or even complete sales of functions to separate companies has come up completely unexpectedly to whomever specified the IT requirements. If that happens life is much easier if the two disparate networks don't share the same layer 3 structure. If the separate groups really have no relation to each other then I would put them into separate subnets as a minimum. Much easier to comprehend the logical structure that way. The VLAN setups you mentioned could all remain the same. I also agree with bypassing the intermediate switches if physically possible, physical complexity is the enemy of stability.