Designing Access Controls

Choose the Endpoint Integrity Deployment Method

Table 3-36. Security Level of Deployment Methods

Inline

802.1X

DHCP

 

 

 

Security provided

High

Security mechanism

The NAC 800 is physically

 

placed between the endpoint

 

and network resources.

High

Compliant endpoints are dynamically assigned a VLAN; non-compliant endpoints are quarantined in a separate VLAN.

Medium

The DHCP server gives a valid IP address only to compliant endpoints; the NAC 800 assigns non-compliant endpoints addresses in quarantine subnets.

Vulnerability

None

None

Sophisticated users can

 

 

 

assign their devices a valid IP

 

 

 

address and avoid making

 

 

 

DHCP requests.

 

 

 

 

Example

Based solely on security concerns, the PCU network administrators would choose the 802.1X deployment method for each access control zone and an inline deployment for remote access. However, the administrators know that they cannot use 802.1X as the deployment method with Web-Auth, which is the access control method in the public zones. So they choose the second most secure deployment method (inline) for the public zones.

Table 3-37. Deployment Method by Security

Factor

Private Wired

Public Wired

Private Wireless

Public Wireless

Remote

Security

802.1X

802.1X

802.1X

802.1X

Inline

Security—after

802.1X

Inline

802.1X

Inline

Inline

access control method

 

 

 

 

 

is considered

 

 

 

 

 

 

 

 

 

 

 

Existing Network Infrastructure

After the access control method, your existing network infrastructure is perhaps the most critical factor for selecting a deployment method.

If you are considering the 802.1X deployment method, your switches must of course support 802.1X. You should also determine whether the switches support traffic mirroring (which may be called port mirroring, port monitor- ing, or port spanning, depending on your switch)—which allows the NAC 800s to detect and test endpoints. Many switches support local traffic mirror- ing—mirroring traffic from one port to another port on the same switch. However, some switches, such as the ProCurve Switches 3500yl, 5400zl, 6200yl, and 8200zl, support remote traffic mirroring as well. With remote

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