Dell PowerConnect 8024, User Configuration Manual

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Configuring VLANs
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attached to promiscuous ports. Then, if one of the servers is compromised,
the intruder cannot use it to attack another server in the same network
segment.
The same traffic isolation can be achieved by assigning each port with a
different VLAN, allocating an IP subnet for each VLAN, and enabling layer 3
routing between them. In a private VLAN domain, on the other hand, all
members can share the common address space of a single subnet, which is
associated with a primary VLAN. So, the advantage of the private VLANs
feature is that it reduces the number of consumed VLANs, improves IP
addressing space utilization, and helps to avoid layer 3 routing.
Figure 22-3 shows an example Private VLAN scenario, in which five hosts (H-
A through H-E) are connected to a stack of switches (SW1, SW2). The
switch stack is connected to router R1. Port references shown are with
reference to the stack.
Figure 22-3. Private VLAN Domain
R1
TE1/1/1
SW1
Gi1/0/10 Gi1/0/11
Gi1/0/12
H-A H-B H-C H-D H-E
Gi2/0/10 Gi2/0/11
SW2