Network isolation practices significantly bolster network security in your vSphere environment.
Isolate the Management Network
The vSphere management network provides access to the vSphere management interface on each component. Services running on the management interface provide an opportunity for an attacker to gain privileged access to the systems. Remote attacks are likely to begin with gaining access to this network. If an attacker gains access to the management network, it provides the staging ground for further intrusion.
Strictly control access to management network by protecting it at the security level of the most secure VM running on an ESXi host or cluster. No matter how the management network is restricted, administrators must have access to this network to configure the ESXi hosts and vCenter Server system.
Place the vSphere management port group in a dedicated VLAN on a common standard switch. Production (VM) traffic can share the standard switch if the vSphere management port group's VLAN is not used by production VMs.
Check that the network segment is not routed, except to networks where other management-related entities are found. Routing a network segment might make sense for vSphere Replication. In particular, make sure that production VM traffic cannot be routed to this network.
Strictly control access to management functionality by using one of the following approaches.
For especially sensitive environments, configure a controlled gateway or other controlled method to access the management network. For example, require that administrators connect to the management network through a VPN. Allow access to the management network only to trusted administrators.
Configure jump boxes that run management clients.
Isolate Storage Traffic
Ensure that IP-based storage traffic is isolated. IP-based storage includes iSCSI and NFS. VMs might share virtual switches and VLANs with the IP-based storage configurations. This type of configuration might expose IP-based storage traffic to unauthorized VM users.
IP-based storage frequently is not encrypted. Anyone with access to this network can view IP-based storage traffic. To restrict unauthorized users from viewing IP-based storage traffic, logically separate the IP-based storage network traffic from the production traffic. Configure the IP-based storage adapters on separate VLANs or network segments from the VMkernel management network to limit unauthorized users from viewing the traffic.
Isolate vMotion Traffic
vMotion migration information is transmitted in plain text. Anyone with access to the network over which this information flows can view it. Potential attackers can intercept vMotion traffic to obtain the memory contents of a VM. They might also stage a MiTM attack in which the contents are modified during migration.
Separate vMotion traffic from production traffic on an isolated network. Set up the network to be nonroutable, that is, make sure that no layer-3 router is spanning this and other networks, to prevent outside access to the network.
Use a dedicated VLAN on a common standard switch for the vMotion port group. Production (VM) traffic can use the same standard switch if the vMotion port group’s VLAN is not used by production VMs.