Cisco Nexus 7000 Series NX-OS Security Configuration Guide, Release 4.1

Configuring Cisco TrustSec

This chapter describes how to configure Cisco TrustSec on Cisco NX-OS devices.

This chapter includes the following sections:

•Information About Cisco TrustSec

•Licensing Requirements for Cisco TrustSec

•Prerequisites for Cisco TrustSec

•Guidelines and Limitations

•Configuring Cisco TrustSec

•Verifying Cisco TrustSec Configuration

•Example Cisco TrustSec Configurations

•Default Settings

•Additional References

•Feature History for Cisco TrustSec

Information About Cisco TrustSec

This section includes the following topics:

•Cisco TrustSec Architecture

•Authentication

•SGACLs and SGTs

•Authorization and Policy Acquisition

•Environment Data Download

•RADIUS Relay Functionality

•Virtualization Support

Cisco TrustSec Architecture

The Cisco TrustSec security architecture builds secure networks by establishing clouds of trusted network devices. Each device in the cloud is authenticated by its neighbors. Communication on the links between devices in the cloud is secured with a combination of encryption, message integrity checks, and data-path replay protection mechanisms. Cisco TrustSec also uses the device and user identification information acquired during authentication for classifying, or coloring, the packets as they enter the network. This packet classification is maintained by tagging packets on ingress to the Cisco TrustSec network so that they can be properly identified for the purpose of applying security and other policy criteria along the data path. The tag, also called the security group tag (SGT), allows the network to enforce the access control policy by enabling the endpoint device to act upon the SGT to filter traffic.

Note Ingress refers to entering the first Cisco TrustSec-capable device encountered by a packet on its path to the destination and egress refers to leaving the last Cisco TrustSec-capable device on the path.

Figure 10-1 shows an example of a Cisco TrustSec cloud. In this example, several networking devices and an endpoint device are inside the Cisco TrustSec cloud. One endpoint device and one networking device are outside the cloud because they are not Cisco TrustSec-capable devices or they have been refused access.

Figure 10-1 Cisco TrustSec Network Cloud Example

The Cisco TrustSec architecture consists of the following major components:

•Authentication—Verifies the identity of each device before allowing them to join the Cisco TrustSec network.

•Authorization—Decides the level of access to the Cisco TrustSec network resources for a device based on the authenticated identity of the device.

•Access Control—Applies access policies on per-packet basis using the source tags on each packet.

•Secure communication—Provides encryption, integrity, and data-path replay protection for the packets that flow over each link in the Cisco TrustSec network.

A Cisco TrustSec network has the following three entities:

•Supplicants—Devices that attempt to join a Cisco TrustSec network.

•Authenticators (AT)—Devices that are already part of a Cisco TrustSec network.

•Authorization server—Servers that may provide authentication information, authorization information, or both.

When the link between the supplicant and the AT first comes up, the following sequence of events may occur:

1. Authentication (802.1X)—The authentication server performs the authentication of the supplicant or the authentication completes trivially if you configure the devices to unconditionally authenticate each other.

2. Authorization—Each side of the link obtains policies, such as SGT and ACLs, that to apply to the link. A supplicant may need to use the AT as a relay if it has no other Layer 3 route to the authentication server.

3. Security Association Protocol (SAP) negotiation—The EAPOL-Key exchange occurs between the supplicant and the AT to negotiate a cipher suite, exchange security parameter indexes (SPIs), and manage keys. Successful completion of all three tasks results in the establishment of a security association (SA).

Ports stay in unauthorized state (blocking state) until the SAP negotiation completes (see Figure 10-2).

Figure 10-2 SAP Negotiation

SAP negotiation can use any of the following modes of operation:

•Galois/Counter Mode (GCM) encryption

•GCM authentication (GMAC)

•No encapsulation (clear text)

•Encapsulation with no encryption or authentication

Based on the IEEE 802.1AE standard, Cisco TrustSec uses ESP-128 GCM and GMAC.

Authentication

Cisco TrustSec authenticates a device before allowing it to join the network. Cisco TrustSec uses 802.1X authentication with Extensible Authentication Protocol Flexible Authentication via Secure Tunnel (EAP-FAST) as the Extensible Authentication Protocol (EAP) method to perform the authentication.

This section includes the following topics:

•Cisco TrustSec and Authentication

•Device Identities

•Device Credentials

•User Credentials

Cisco TrustSec and Authentication

Cisco TrustSec uses EAP-FAST for authentication. EAP-FAST conversations allow for other EAP method exchanges inside the EAP-FAST tunnel using chains. This allows administrators to use traditional user authentication methods, such as Microsoft Challenge Handshake Authentication Protocol Version 2 (MSCHAPv2), while still having security provided by the EAP-FAST tunnel. Figure 10-3 shows the EAP-FAST tunnel and inner methods as used in Cisco TrustSec.

Figure 10-3 Cisco TrustSec Authentication

This section includes the following topics:

•Cisco TrustSec Enhancements to EAP-FAST

•802.1x Role Selection

•Cisco TrustSec Authentication Summary

Cisco TrustSec Enhancements to EAP-FAST

The implementation of EAP-FAST for Cisco TrustSec has the following enhancements:

•Authenticate the authenticator—Securely determines the identity of the AT by requiring the AT to use its protected access credential (PAC) to derive the shared secret between itself and the authentication server. This feature also prevents you from configuring RADIUS shared secrets on the authentication server for every possible IP address that can be used by the AT.

•Notify each peer of the identity of its neighbor—By the end of the authentication exchange, the authentication server has identified both the supplicant and the AT. The authentication server conveys the identity of the AT, and whether the AT is Cisco TrustSec-capable, to the supplicant by using additional type-length-value parameters (TLVs) in the protected EAP-FAST termination. The authentication server also conveys the identity of the supplicant and whether the supplicant is Cisco TrustSec-capable, to the AT by using RADIUS attributes in the Access- Accept message. Because each peer knows the identity of its neighbor, it can send additional RADIUS Access-Requests to the authentication server to acquire the policy to be applied on the link.

•AT posture evaluation—The AT provides its posture information to the authentication server whenever it starts the authentication exchange with the authentication server on behalf of the supplicant.

802.1x Role Selection

In 802.1X, the AT must have IP connectivity with the authentication server because it has to relay the authentication exchange between the supplicant and the AT using RADIUS over UDP/IP. When an endpoint device, such as a PC, connects to a network, it is obvious that it should act as a supplicant. However, in the case of a Cisco TrustSec connection between two network devices, the 802.1X role of each network device might not be immediately apparent to the other network device.

Instead of requiring manual configuration of the AT and supplicant roles for the Cisco NX-OS devices, Cisco TrustSec runs a role-selection algorithm to automatically determine which Cisco NX-OS device acts as the AT and which acts as the supplicant. The role-selection algorithm assigns the AT role to the device that has IP reachability to a RADIUS server. Both devices start both the AT and supplicant state machines. When a Cisco NX-OS device detects that its peer has access to a RADIUS server, it terminates its own AT state machine and assumes the role of the supplicant. If both Cisco NX-OS devices have access to a RADIUS server, the algorithm compares the MAC addresses used as the source for sending the EAP over LAN (EAPOL) packets. The Cisco NX-OS device that has the MAC address with the higher value becomes the AT and the other Cisco NX-OS device becomes the supplicant.

Cisco TrustSec Authentication Summary

By the end of the Cisco TrustSec authentication process, the authentication server has performed the following actions:

•Verified the identities of the supplicant and the AT.

•Authenticated the user if the supplicant is an endpoint device.

At the end of the Cisco TrustSec authentication process, both the AT and the supplicant know following:

•Device ID of the peer

•Cisco TrustSec capability information of the peer

•Key used for the SAP

Device Identities

Cisco TrustSec does not use IP addresses or MAC addresses as device identities. Instead, you assign a name (device ID) to each Cisco TrustSec-capable Cisco NX-OS device to identify it uniquely in the Cisco TrustSec network. This device ID used for the following:

•Looking up authorization policy

•Looking up passwords in the databases during authentication

Device Credentials

Cisco TrustSec supports password-based credentials. The authentication servers may use self-signed certificates instead. Cisco TrustSec authenticates the supplicants through passwords and uses MSCHAPv2 to provide mutual authentication even if the authentication server certificate is not verifiable.

The authentication server uses these credentials are to mutually authenticate the supplicant during the EAP-FAST phase 0 (provisioning) exchange where a PAC is provisioned in the supplicant. Cisco TrustSec does not perform the EAP-FAST phase 0 exchange again until the PAC expires, and only performs EAP-FAST phase 1 and phase 2 exchanges for future link bringups. The EAP-FAST phase 1 exchange uses the PAC to mutually authenticate the authentication server and the supplicant. Cisco TrustSec uses the device credentials only during the PAC provisioning (or reprovisioning) steps.

The authentication server uses a temporarily configured password to authenticate the supplicant when the supplicant first joins the Cisco TrustSec network. When the supplicant first joins the Cisco TrustSec network, the authentication server authenticates the supplicant using a manufacturing certificate and then generates a strong password and pushes it to the supplicant with the PAC. The authentication server also keeps the new password in its database. The authentication server and the supplicant use this password for mutual authentication in all future EAP-FAST phase 0 exchanges.

User Credentials

Cisco TrustSec does not require a specific type of user credentials for endpoint devices. You can choose any type of authentication method for the user (for example, MSCHAPv2, LEAP, generic token card (GTC), or OTP) and use the corresponding credentials. Cisco TrustSec performs user authentication inside the EAP-FAST tunnel as part of the EAP-FAST phase 2 exchange.

SGACLs and SGTs

In security group access lists (SGACLs), you can control the operations that users can perform based on assigned security groups. The grouping of permissions into a role simplifies the management of the security policy. As you add users to the Cisco NX-OS device, you simply assign one or more security groups and they immediately receive the appropriate permissions. You can modify security groups to introduce new privileges or restrict current permissions.

Cisco TrustSec assigns a unique 16-bit tag, called the security group tag (SGT), to a security group. The number of SGTs in the Cisco NX-OS device is limited to the number of authenticated network entities. The SGT is a single label that indicates the privileges of the source within the entire enterprise. Its scope is global within a Cisco TrustSec network.

The management server derives the SGTs based on the security policy configuration. You do not have to configure them manually.

Once authenticated, Cisco TrustSec tags any packet that originates from a device with the SGT that represents the security group to which the device is assigned. The packet carries this SGT throughout the network within the Cisco TrustSec header. Because this tag represents the group of the source, the tag is referred to as the source SGT. At the egress edge of the network, Cisco TrustSec determines the group that is assigned to the packet destination device and applies the access control policy.

Cisco TrustSec defines access control policies between the security groups. By assigning devices within the network to security groups and applying access control between and within the security groups, Cisco TrustSec essentially achieves access control within the network. Figure 10-4 shows an example of an SGACL policy.

Figure 10-4 SGACL Policy Example

Figure 10-5 shows how the SGT assignment and the SGACL enforcement operate in a Cisco TrustSec network.

Figure 10-5 SGT and SGACL in Cisco TrustSec Network

The Cisco NX-OS device defines Cisco TrustSec access control policy for a group of devices as opposed to IP addresses in traditional ACLs. With such a decoupling, the network devices are free to move throughout the network and change IP addresses. Entire network topologies can change. As long as the roles and the permissions remain the same, changes to the network do not change the security policy. This greatly reduces size of ACLs and simplifies their maintenance.

In traditional IP networks, the number of access control entries (ACEs) configured is determined as follows:

# of ACEs = (# of sources specified) X (# of destinations specified) X (# of permissions specified)

In Cisco TrustSec uses the following formula:

# of ACEs = # of permissions specified

This section includes the following topics:

•Determining the Source Security Group

•Determining the Destination Security Group

•SXP for SGT Propagation Across Legacy Access Networks

Determining the Source Security Group

A network device at the ingress of Cisco TrustSec cloud needs to determine the SGT of the packet entering the Cisco TrustSec cloud so that it can tag the packet with that SGT when it forwards it into the Cisco TrustSec cloud. The egress network device needs to determine SGT of the packet to apply the SGACLs.

The network device can determine the SGT for a packet in one of the following methods:

•Obtain the source SGT during policy acquisition—After Cisco TrustSec authentication phase, network device acquires policy from authentication server. Authentication server indicates whether the peer device is trusted or not. If a peer device is not trusted then the authentication server can also provide an SGT to apply to all packets coming from the peer device.

•Obtain the source SGT field from the Cisco TrustSec header—If a packet comes from a trusted peer device, the Cisco TrustSec header carries the correct SGT field. This applies to a network device which is not the first network device in Cisco TrustSec cloud for the packet.

•Look up the source SGT based on source IP Address—In some cases, you can manually configure the policy to decide the SGT of a packet based on source IP address. The SGT Exchange Protocol (SXP) can also populate the IP-address-to-SGT mapping table.

Determining the Destination Security Group

The egress network device in a Cisco TrustSec cloud determines the destination group for applying the SGACL. In some cases, ingress devices or other non-egress devices might have destination group information available. In those cases SGACLs might be applied in these devices rather than egress devices.

Cisco TrustSec determines the destination group for the packet in following ways:

•Destination SGT of the egress port obtained during policy acquisition

•Destination SGT lookup based on the destination IP address

SXP for SGT Propagation Across Legacy Access Networks

The Cisco NX-OS device hardware in the access layer supports Cisco TrustSec. Without the Cisco TrustSec hardware, the Cisco TrustSec software cannot tag the packets with SGTs. You can use SXP to propagate the SGTs across network devices that do not have hardware support for Cisco TrustSec.

SXP operates between access layer devices and distribution layer devices. The access layer devices use SXP to pass the IP addresses of the Cisco TrustSec authenticated devices along with their SGTs to the distribution switches. Distribution devices with both Cisco TrustSec-enable software and hardware can use this information to tag packets appropriately and enforce SGACL policies (see Figure 10-6).

Figure 10-6 SXP Protocol to Propagate SGT information

Tagging packets with SGTs requires hardware support. You might have devices in your network that cannot tag packets with SGTs. To allow these devices to send IP address-to-SGT mappings to a device that has Cisco TrustSec-capable hardware, you must manually set up the SXP connections. Manually setting up an SXP connection requires the following:

•ïIf you require SXP data integrity and authentication, you must configure both the same SXP password on both of the peer devices. You can configure the SXP password either explicitly for each peer connection or globally for the device. The SXP password is not required.

•ïYou must configure each peer on the SXP connection as either an SXP speaker or an SXP listener. The speaker device distributes the SXP information to the listener device.

•You can specify a source IP address to use for each peer relationship or you can configure a default source IP address for peer connections where you have not configured a specific source IP address.

Authorization and Policy Acquisition

After authentication ends, both the supplicant and AT obtain the security policy from the authentication server. The supplicant and AT enforce the policy against each other. Both the supplicant and AT provide the peer device ID that each receives after authentication. If the peer device ID is not available, Cisco TrustSec can use a manually configured peer device ID.

The authentication server returns the following policy attributes:

•Cisco TrustSec trust—Indicates whether the neighbor device is to be trusted for the purpose of putting the SGT in the packets.

•Peer SGT—Indicates the security group that the peer belongs to. If the peer is not trusted, all packets received from the peer are tagged with this SGT. If the device does not know if the SGACLs are associated with the peer's SGT, the device may send a follow-up request to fetch the SGACLs.

•Authorization expiry time—Indicates the number of seconds before the policy expires. The Cisco-proprietary attribute-value (AV) pairs indicates the expiration time of an authorization or policy response to a Cisco TrustSec device. A Cisco TrustSec device should refresh its policy and authorization before it times out.

Tip Each Cisco TrustSec device should support some minimal default access policy in case it is not able to contact the authentication server to get an appropriate policy for the peer.

Environment Data Download

The Cisco TrustSec environment data is a collection of information or policies that assists a device to function as a Cisco TrustSec node. The device acquires the environment data from the authentication server when the device first joins a Cisco TrustSec cloud, although you might also manually configure some of the data on a device. For example, you must configure the seed Cisco TrustSec device with the authentication server information, which can later be augmented by the server list that the device acquires from the authentication server.

The device must refresh the Cisco TrustSec environment data before it expires.

The device uses RADIUS to acquire the following environment data from the authentication server:

•Server lists—List of servers that the client can use for future RADIUS requests (for both authentication and authorization).

•Device SGT—Security group to which the device itself belongs.

•Expiry timeout—Interval that controls how often the Cisco TrustSec device should refresh its environment data.

RADIUS Relay Functionality

The Cisco NX-OS device that plays the role of the Cisco TrustSec AT in the 802.1X authentication process has IP connectivity to the authentication server, which allows it to acquire the policy and authorization from the authentication server by exchanging RADIUS messages over UDP/IP. The supplicant device may not have IP connectivity with the authentication server. In such cases, Cisco TrustSec allows the AT to act as a RADIUS relay for the supplicant.

The supplicant sends a special EAP over LAN (EAPOL) message to the Cisco TrustSec AT that contains the RADIUS server IP address and UDP port and the complete RADIUS request. The Cisco TrustSec AT extracts the RADIUS request from the received EAPOL message and sends it over UDP/IP to the authentication server. When the RADIUS response returns from the authentication server, the Cisco TrustSec AT forwards the message back to the supplicant, encapsulated in an EAPOL frame.

Virtualization Support

Cisco TrustSec configuration and operation are local to the virtual device context (VDC). For more information on VDCs, see the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 4.1.

Licensing Requirements for Cisco TrustSec

The following table shows the licensing requirements for this feature:

Prerequisites for Cisco TrustSec

Cisco TrustSec has the following prerequisites:

•You must install the Advance Service license.

•You must enable the 802.1X feature.

Guidelines and Limitations

Cisco TrustSec has the following guidelines and limitations:

•Cisco TrustSec uses RADIUS for authentication.

•You cannot configure both Cisco TrustSec and 802.1X on an interface; you can configure only one or the other. However, you must enable the 802.1X feature for Cisco TrustSec to use EAP-FAST authentication.

•AAA authentication and authorization for Cisco TrustSec is only supported by the Cisco Secure Access Control Server (ACS).

•Cisco TrustSec supports IPv4 addressing only.

•SXP cannot use the management (mgmt 0) interface.

•You cannot enable Cisco TrustSec on interfaces in half-duplex mode.

•Do not perform simultaneous in-service software upgrades (ISSUs) on Cisco NX-OS devices you have connected using Cisco TrustSec. Wait until the ISSU for one device completes before you upgrade the other device.

Configuring Cisco TrustSec

This section includes the following topics:

•Enabling the Cisco TrustSec Feature

•Configuring Cisco TrustSec Device Credentials

•Configuring AAA for Cisco TrustSec

•Configuring Cisco TrustSec Authentication, Authorization, SAP, and Data Path Security

•Configuring Cisco TrustSec Authentication in Manual Mode

•Configuring SGACL Policies

•Manually Configuring SXP

Enabling the Cisco TrustSec Feature

You must enable both the 802.1X and Cisco TrustSec features on the Cisco NX-OS device before you can configure Cisco TrustSec.

Note You cannot disable the 802.1X feature after you enable the Cisco TrustSec feature.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

SUMMARY STEPS

1. configure terminal

2. feature dot1x

3. feature cts

4. exit

5. show feature

6. copy running-config startup-config

DETAILED STEPS

Configuring Cisco TrustSec Device Credentials

You must configure unique Cisco TrustSec credentials on each Cisco TrustSec-enabled Cisco NX-OS device in your network. Cisco TrustSec uses the password in the credentials for device authentication.

Note You must also configure the Cisco TrustSec credentials for the Cisco NX-OS device on the Cisco Secure ACS (see the Configuration Guide for the Cisco Secure ACS).

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. configure terminal

2. cts device-id name password password

3. exit

4. show cts

5. copy running-config startup-config

DETAILED STEPS

Configuring AAA for Cisco TrustSec

You can use Cisco Secure ACS for Cisco TrustSec authentication. You must configure RADIUS server groups and specify the default AAA authentication and authorization methods on one of the Cisco TrustSec-enabled Cisco NX-OS devices in your network cloud. Because Cisco TrustSec supports RADIUS relay, you need to configure AAA only on a seed Cisco NX-OS device that is directly connected to a Cisco Secure ACS. For all the other Cisco TrustSec-enable Cisco NX-OS devices, Cisco TrustSec automatically provides a private AAA server group, aaa-private-sg. The seed Cisco NX-OS devices uses the management VRF to communicate with the Cisco Secure ACS.

Note Only the Cisco Secure ACS supports Cisco TrustSec.

For more information on configuring RADIUS servers, see Chapter 3, "Configuring RADIUS." For information on configuring RADIUS server groups, see Chapter 2, "Configuring AAA."

This section includes the following sections:

•Configuring AAA on the Cisco TrustSec Seed Cisco NX-OS Device

•Configuring AAA on Cisco TrustSec Nonseed Cisco NX-OS Devices

Configuring AAA on the Cisco TrustSec Seed Cisco NX-OS Device

This section describes how to configure AAA on the seed Cisco NX-OS device in your Cisco TrustSec network cloud.

Note When you configure the AAA RADIUS server group for the seed Cisco NX-OS device, you must specify a VRF. If you use the management VRF, no further configuration is necessary for the nonseed devices in the network cloud. If you use a different VRF, you must configure the nonseed devices with that VRF (see the Configuring AAA on Cisco TrustSec Nonseed Cisco NX-OS Devices).

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Obtain the IPv4 or IPv6 address or hostname for the Cisco ACS.

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. configure terminal

2. radius-server host {ipv4-address | ipv6-address | hostname} password password pac

3. show radius-server

4. aaa group server radius group-name

5. server {ipv4-address | ipv6-address | hostname}

6. use-vrf vrf-name

7. exit

8. aaa authentication dot1x default group group-name

9. aaa authorization cts default group group-name

10. exit

11. show radius-server groups [group-name]

12. show aaa authentication

13. show aaa authorization

14. show cts pacs

15. copy running-config startup-config

DETAILED STEPS

Configuring AAA on Cisco TrustSec Nonseed Cisco NX-OS Devices

Cisco TrustSec configures an AAA server group named aaa-private-sg on the nonseed Cisco NX-OS devices in the network cloud. By default, the aaa-private-sg server group uses the management VRF to communicate with the Cisco Secure ACS and no further configuration is required on the nonseed Cisco NX-OS devices. However, if you choose to use a different VRF, you must change the aaa-private-sg on the nonseed Cisco NX-OS device to use the correct VRF.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you have configured a seed Cisco NX-OS device in your network (see Configuring AAA on the Cisco TrustSec Seed Cisco NX-OS Device).

SUMMARY STEPS

1. configure terminal

2. aaa group server radius aaa-private-sg

3. use-vrf vrf-name

4. exit

5. show radius-server groups [group-name]

6. copy running-config startup-config

DETAILED STEPS

Configuring Cisco TrustSec Authentication, Authorization, SAP, and Data Path Security

This section includes the following topics:

•Enabling Cisco TrustSec Authentication

•Configuring Data-Path Replay Protection for Cisco TrustSec on Interfaces

•Configuring SAP Operation Modes for Cisco TrustSec on Interfaces

•Configuring SGT Propagation for Cisco TrustSec on Interfaces

•Regenerating SAP Keys on an Interface

Cisco TrustSec Configuration Process for Cisco TrustSec Authentication and Authorization

Follow these steps to configure Cisco TrustSec authentication and authorization:

Step 1 Enable the Cisco TrustSec feature (see the "Enabling the Cisco TrustSec Feature" section).

Step 2 Enable Cisco TrustSec authentication (see the "Enabling Cisco TrustSec Authentication" section).

Step 3 Enable 802.1X authentication for Cisco TrustSec on the interfaces (see the "Enabling Cisco TrustSec Authentication" section).

Enabling Cisco TrustSec Authentication

You must enable Cisco TrustSec authentication on the interfaces. By default, the data path replay protection feature is enabled and the SAP operating mode is GCM-encrypt.

Caution For the Cisco TrustSec authentication configuration to take affect, you must enable and disable the interface which disrupts traffic on the interface.

Note Enabling 802.1X mode for Cisco TrustSec automatically enables authorization and SAP on the interface.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

SUMMARY STEPS

1. configure terminal

2. interface ethernet slot/port [- port2]

3. cts dot1x

4. no data-path replay protection

5. sap modelist {gmc-encrypt | gmac | no-encap | null}

6. exit

7. shutdown

8. no shutdown

9. exit

10. show cts interface all

11. copy running-config startup-config

DETAILED STEPS

Configuring Data-Path Replay Protection for Cisco TrustSec on Interfaces

By default, the Cisco NX-OS software enables the data-path reply protection feature. You can disable the data-path replay protection feature on the interfaces for Layer 2 Cisco TrustSec if the connecting device does not support SAP.

Caution For the data-path replay protection configuration to take affect, you must enable and disable the interface which disrupts traffic on the interface.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec authentication on the interface (see the "Enabling Cisco TrustSec Authentication" section).

SUMMARY STEPS

1. configure terminal

2. interface ethernet slot/port [- port2]

3. cts dot1x

4. no replay-protection

5. exit

6. shutdown

7. no shutdown

8. exit

9. show cts interface all

10. copy running-config startup-config

DETAILED STEPS

Configuring SAP Operation Modes for Cisco TrustSec on Interfaces

You can configure the SAP operation mode on the interfaces for Layer 2 Cisco TrustSec. The default SAP operation mode is GCM-encrypt.

Caution For the SAP operation mode configuration to take affect, you must enable and disable the interface which disrupts traffic on the interface.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec authentication on the interface (see the "Enabling Cisco TrustSec Authentication" section).

SUMMARY STEPS

1. configure terminal

2. interface ethernet slot/port [- port2]

3. cts dot1x

4. sap modelist gcm-encrypt

sap modelist gmac

sap modelist no-encap

sap modelist null

5. exit

6. shutdown

7. no shutdown

8. exit

9. show cts interface all

10. copy running-config startup-config

DETAILED STEPS

Configuring SGT Propagation for Cisco TrustSec on Interfaces

SGT propagation feature on the Layer 2 interface is enabled by default. You can disable the SGT propagation feature on an interface if the peer device connected to the interface can not handle Cisco TrustSec packets tagged with an SGT.

Caution For the SGT propagation configuration to take affect, you must enable and disable the interface which disrupts traffic on the interface.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec authentication on the interface (see the "Enabling Cisco TrustSec Authentication" section).

SUMMARY STEPS

1. configure terminal

2. interface ethernet slot/port [- port2]

3. cts dot1x

4. no propagate-sgt

5. exit

6. shutdown

7. no shutdown

8. exit

9. show cts interface all

10. copy running-config startup-config

DETAILED STEPS

Regenerating SAP Keys on an Interface

You can trigger an SAP protocol exchange to generate a new set of keys and protect the data traffic flowing on an interface.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. cts rekey ethernet slot/port

2. show cts interface all

DETAILED STEPS

Configuring Cisco TrustSec Authentication in Manual Mode

You can manually configure Cisco TrustSec on an interface if your Cisco NX-OS device does not have access to a Cisco Secure ACS or authentication is not needed because you have the MAC address authentication bypass feature enabled. You must manually configure the interfaces on both ends of the connection.

Note You cannot enable Cisco TrustSec on interfaces in half-duplex mode. Use the show interface command to determine if an interface is configure for half-duplex mode.

Caution For the Cisco TrustSec manual mode configuration to take affect, you must enable and disable the interface which disrupts traffic on the interface.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. configure terminal

2. interface ethernet slot/port

3. cts manual

4. sap pmk {key | use-dot1x} [modelist {gcm-encrypt | gmac | no-encap | null}]

5. policy dynamic identity peer-name

policy static sgt tag [trusted]

6. exit

7. shutdown

8. no shutdown

9. exit

10. show cts interface all

11. copy running-config startup-config

DETAILED STEPS

Configuring SGACL Policies

This section includes the following topics:

•SGACL Policy Configuration Process

•Enabling SGACL Policy Enforcement on VLANs

•Enabling SGACL Policy Enforcement on VRFs

•Manually Configuring IPv4-Address-to-SGACL SGT Mapping

•Manually Configuring SGACL Policies

•Displaying the Downloaded SGACL Policies

•Refreshing the Downloaded SGACL Policies

•Clearing Cisco TrustSec SGACL Policies

SGACL Policy Configuration Process

Follow these steps to configure Cisco TrustSec SGACL policies:

Step 1 For Layer 2 interfaces, enable SGACL policy enforcement for the VLANs with Cisco TrustSec-enabled interfaces (see the "Enabling SGACL Policy Enforcement on VLANs" section).

Step 2 For Layer 3 interfaces, enable SGACL policy enforcement for the VRFs with Cisco TrustSec-enabled interfaces (see the "Enabling SGACL Policy Enforcement on VRFs" section).

Step 3 If you are not using AAA on a Cisco Secure ACS to download the SGACL policy configuration, manually configure the SGACL mapping and policies (see the "Manually Configuring IPv4-Address-to-SGACL SGT Mapping" section and the "Manually Configuring SGACL Policies" section).

Enabling SGACL Policy Enforcement on VLANs

If you use SGACLs, you must enable SGACL policy enforcement in the VLANs that have Cisco TrustSec-enabled Layer 2 interfaces.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. configure terminal

2. vlan vlan-id

3. cts role-based enforcement

4. exit

5. show cts role-based enable

6. copy running-config startup-config

DETAILED STEPS

Enabling SGACL Policy Enforcement on VRFs

If you use SGACLs, you must enable SGACL policy enforcement in the VRFs that have Cisco TrustSec-enabled Layer 3 interfaces.

Note You cannot enable SGACL policy enforcement on the management VRF.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you enabled dynamic Address Resolution Protocol (ARP) inspection (see Chapter 16, "Configuring Dynamic ARP Inspection") or Dynamic Host Configuration Protocol (DHCP) snooping (see Chapter 15, "Configuring DHCP Snooping").

SUMMARY STEPS

1. configure terminal

2. vrf context vrf-name

3. cts role-based enforcement

4. exit

5. show cts role-based enable

6. copy running-config startup-config

DETAILED STEPS

Manually Configuring Cisco TrustSec SGTs

You can manually configure unique Cisco TrustSec security group tags (SGTs) for the packets subject to SGACL enforcement.

Note You must also configure the Cisco TrustSec credentials for the Cisco NX-OS device on the Cisco Secure ACS.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

SUMMARY STEPS

1. configure terminal

2. cts sgt tag

3. exit

4. show cts environment-data

5. copy running-config startup-config

DETAILED STEPS

Manually Configuring IPv4-Address-to-SGACL SGT Mapping

You can manually configure IPv4 address to SGACL SGT mapping on either a VLAN or a VRF if a Cisco Secure ACS is not available to download the SGACL policy configuration. You can use this feature if you do not have Cisco Secure ACS, dynamic ARP inspection, or DHCP snooping available on your Cisco NX-OS device.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you enabled SGACL policy enforcement on the VLAN (see the "Enabling SGACL Policy Enforcement on VLANs" section) or VRF (see the "Enabling SGACL Policy Enforcement on VRFs" section).

SUMMARY STEPS

1. configure terminal

2. vlan vlan-id

vrf context vrf-name

3. cts role-based sgt-map ipv4-address tag

4. exit

5. show cts role-based enable

6. copy running-config startup-config

DETAILED STEPS

Manually Configuring SGACL Policies

You can manually configure SGACL polices on your Cisco NX-OS device if a Cisco Secure ACS is not available to download the SGACL policy configuration.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you enabled SGACL policy enforcement on the VLAN (see the "Enabling SGACL Policy Enforcement on VLANs" section) and VRF (see the "Enabling SGACL Policy Enforcement on VRFs" section).

SUMMARY STEPS

1. configure terminal

2. cts role-based access-list list-name

3. deny all

deny icmp

deny igmp

deny ip

deny tcp [{dest | src} {{eq | gt | lt | neq} port-number | range port-number1 port-number2}]

deny udp [{dest | src} {{eq | gt | lt | neq} port-number | range port-number1 port-number2}]

4. permit all

permit icmp

permit igmp

permit ip

permit tcp [{dest | src} {{eq | gt | lt | neq} port-number | range port-number1 port-number2}]

permit udp [{dest | src} {{eq | gt | lt | neq} port-number | range port-number1 port-number2}]

5. exit

6. cts role-based sgt {sgt-value | any | unknown} dgt {dgt-value | any | unknown}
access-list list-name

7. show cts role-based access-list

8. copy running-config startup-config

DETAILED STEPS

Displaying the Downloaded SGACL Policies

After you configure the Cisco TrustSec device credentials and AAA, you can verify the Cisco TrustSec SGACL policies downloaded from the Cisco Secure ACS. The Cisco NX-OS software download the SGACL policies when it learns of a new SGT through authentication and authorization on an interface, from SXP, or from manual IPv4 address to SGACL SGT mapping.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. show cts role-based access-list

DETAILED STEPS

Refreshing the Downloaded SGACL Policies

You can refresh the SGACL policies downloaded to the Cisco NX-OS device by the Cisco Secure ACS.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. cts refresh role-based-policy

2. show cts role-based policy

DETAILED STEPS

Clearing Cisco TrustSec SGACL Policies

You can clear the Cisco TrustSec SGACL policies.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. clear cts policy {all | peer device-name | sgt sgt-value}

2. show cts role-based policy

DETAILED STEPS

Manually Configuring SXP

You can use the SGT Exchange Protocol (SXP) to propagate the SGTs across network devices that do not have hardware support for Cisco TrustSec. This section describes how to configure Cisco TrustSec SXP on Cisco NX-OS devices in your network.

This section includes the following topics:

•Cisco TrustSec Configuration Process for Cisco TrustSec Authentication and Authorization

•Enabling Cisco TrustSec SXP

•Configuring Cisco TrustSec SXP Peer Connections

•Configuring the Default SXP Password

•Configuring the Default SXP Source IP Address

•Changing the SXP Reconcile Period

•Changing the SXP Retry Period

Cisco TrustSec SXP Configuration Process

Follow these steps to manually configure Cisco TrustSec SXP:

Step 1 Enable the Cisco TrustSec feature (see the "Enabling the Cisco TrustSec Feature" section).

Step 2 Enable SGACL policy enforcement on the VRF (see the "Enabling SGACL Policy Enforcement on VRFs" section).

Step 3 Enable Cisco TrustSec SXP (see the "Enabling Cisco TrustSec SXP" section).

Step 4 Configure SXP peer connections (see the "Configuring Cisco TrustSec SXP Peer Connections" section).

Note You cannot use the management (mgmt 0) connection for SXP.

Enabling Cisco TrustSec SXP

You must enable Cisco TrustSec SXP before you can configure peer connections.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

SUMMARY STEPS

1. configure terminal

2. cts sxp enable

3. exit

4. show cts sxp

5. copy running-config startup-config

DETAILED STEPS

Configuring Cisco TrustSec SXP Peer Connections

You must configure the SXP peer connection on both of the devices. One device is the speaker and the other is the listener. When using password protection, make sure to use the same password on both ends.

In Cisco NX-OS Release 4.1(3) and later releases, you can specify encrypted passwords for SXP peer connections.

Note If the default SXP source IP address is not configured and you do not specify the SXP source address in the connection, the Cisco NX-OS software derives the SXP source IP address from existing local IP addresses. The SXP source address could be different for each TCP connection initiated from the Cisco NX-OS device.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you enabled SXP (see the "Enabling Cisco TrustSec SXP" section).

Ensure that you enabled RBACL policy enforcement in the VRF (see the "Enabling SGACL Policy Enforcement on VRFs" section).

SUMMARY STEPS

1. configure terminal

2. cts sxp connection peer peer-ipv4-addr [source src-ipv4-addr] password {default | none | required {password | 7 encrypted-password}} mode {speaker | listener} [vrf vrf-name]

3. exit

4. show cts sxp

5. copy running-config startup-config

DETAILED STEPS

Configuring the Default SXP Password

By default, SXP uses no password when setting up connections. You can configure a default SXP password for the Cisco NX-OS device.

In Cisco NX-OS Release 4.1(3) and later releases, you can specify encrypted passwords for SXP default password.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you enabled SXP (see the "Enabling Cisco TrustSec SXP" section).

SUMMARY STEPS

1. configure terminal

2. cts sxp default password {password | 7 encrypted-password}

3. exit

4. show cts sxp

5. show running-config cts

6. copy running-config startup-config

DETAILED STEPS

Configuring the Default SXP Source IP Address

The Cisco NX-OS software uses default source IP address in all new TCP connections where a source IP address is not specified. There is no effect on existing TCP connections when you configure the default SXP source IP address.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you enabled SXP (see the "Enabling Cisco TrustSec SXP" section).

SUMMARY STEPS

1. configure terminal

2. cts sxp default source-ip src-ip-addr

3. exit

4. show cts sxp

5. copy running-config startup-config

DETAILED STEPS

Changing the SXP Reconcile Period

After a peer terminates an SXP connection, an internal hold-down timer starts. If the peer reconnects before the internal hold-down timer expires, the SXP reconcile period timer starts. While the SXP reconcile period timer is active, the Cisco NX-OS software retains the SGT mapping entries learned from the previous connection and removes invalid entries. The default value is 120 seconds (2 minutes). Setting the SXP reconcile period to 0 seconds disables the timer and causes all entries from the previous connection to be removed.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you enabled SXP (see the "Enabling Cisco TrustSec SXP" section).

SUMMARY STEPS

1. configure terminal

2. cts sxp reconcile-period seconds

3. exit

4. show cts sxp

5. copy running-config startup-config

DETAILED STEPS

Changing the SXP Retry Period

The SXP retry period determines how often the Cisco NX-OS software retries an SXP connection. When an SXP connection is not successfully set up, the Cisco NX-OS software makes a new attempt to set up the connection after the SXP retry period timer expires. The default value is 60 seconds (1 minute). Setting the SXP retry period to 0 seconds disables the timer and retries are not attempted.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you enabled Cisco TrustSec (see the "Enabling the Cisco TrustSec Feature" section).

Ensure that you enabled SXP (see the "Enabling Cisco TrustSec SXP" section).

SUMMARY STEPS

1. configure terminal

2. cts sxp retry-period seconds

3. exit

4. show cts sxp

5. copy running-config startup-config

DETAILED STEPS

Verifying Cisco TrustSec Configuration

To display Cisco TrustSec configuration information, perform one of the following tasks:

For detailed information about the fields in the output from this command, see the Cisco Nexus 7000 Series NX-OS Security Command Reference, Release 4.1.

Example Cisco TrustSec Configurations

This sections includes the following topics:

•Enabling Cisco TrustSec

•Configuring AAA for Cisco TrustSec on a Seed Cisco NX-OS Device

•Enabling Cisco TrustSec Authentication on an Interface

•Configuring Cisco TrustSec Authentication in Manual Mode

•Configuring Cisco TrustSec Role-Based Policy Enforcement for the default VRF

•Configuring Cisco TrustSec Role-Based Policy Enforcement for a Nondefault VRF

•Configuring Cisco TrustSec Role-Based Policy Enforcement for a VLAN

•Configuring IPv4 Address to SGACL SGT Mapping for the Default VRF

•Configuring IPv4 Address to SGACL SGT Mapping for a Nondefault VRF

•Configuring IPv4 Address to SGACL SGT Mapping for a VLAN

•Manually Configuring Cisco TrustSec SGACLs

•Manually Configuring SXP Peer Connections

•Manually Configuring SXP Peer Connections

Enabling Cisco TrustSec

The following example shows how to enable Cisco TrustSec:

feature dot1x 

feature cts

cts device-id device1 password Cisco321

Configuring AAA for Cisco TrustSec on a Seed Cisco NX-OS Device

The following example shows how to configure AAA for Cisco TrustSec on the seed device:

radius-server host 10.10.1.1 key Cisco123 pac

aaa group server radius Rad1

  server 10.10.1.1

  use-vrf management

aaa authentication dot1x default group Rad1

aaa authorization cts default group Rad1

Enabling Cisco TrustSec Authentication on an Interface

The following example shows how to enable Cisco TrustSec authentication with a clear text password on an interface:

interface ethernet 2/1

  cts dot1x 

shutdown 

no shutdown

The following example shows how to enable Cisco TrustSec authentication with a clear text password on an interface:

interface ethernet 2/1

  cts dot1x 

shutdown 

no shutdown

Configuring Cisco TrustSec Authentication in Manual Mode

The following example shows how to configure Cisco TrustSec authentication in manual mode an interface:

interface ethernet 2/1

  cts manual 

    sap pmk abcdef modelist gmac 

    policy static sgt 0x20

interface ethernet 2/2

  cts manual 

    policy dynamic identity device2 

Configuring Cisco TrustSec Role-Based Policy Enforcement for the default VRF

The following example shows how to enable Cisco TrustSec role-based policy enforcement for the default VRF:

cts role-based enforcement 

Configuring Cisco TrustSec Role-Based Policy Enforcement for a Nondefault VRF

The following example shows how to enable Cisco TrustSec role-based policy enforcement for a nondefault VRF:

vrf context test

  cts role-based enforcement

Configuring Cisco TrustSec Role-Based Policy Enforcement for a VLAN

The following example shows how to enable Cisco TrustSec role-based policy enforcement for a VLAN:

vlan 10

  cts role-based enforcement

Configuring IPv4 Address to SGACL SGT Mapping for the Default VRF

The following example shows how to manually configure IPv4 address to SGACL SGT mapping for Cisco TrustSec role-based policies for the default VRF:

cts role-based sgt-map 10.1.1.1 20

Configuring IPv4 Address to SGACL SGT Mapping for a Nondefault VRF

The following example shows how to manually configure IPv4 address to SGACL SGT mapping for Cisco TrustSec role-based policies for a nondefault VRF:

vrf context test

  cts role-based sgt-map 30.1.1.1 30

Configuring IPv4 Address to SGACL SGT Mapping for a VLAN

The following example shows how to manually configure IPv4 address to SGACL SGT mapping for Cisco TrustSec role-based policies for a VLAN:

vlan 10

cts role-based sgt-map 20.1.1.1 20

Manually Configuring Cisco TrustSec SGACLs

The following example shows how to manually configure Cisco TrustSec SGACLs:

cts role-based access-list abcd

  permit icmp 

cts role-based sgt 10 dgt 20 access-list abcd

Manually Configuring SXP Peer Connections

Figure 10-7 shows an example of SXP peer connections over the default VRF.

Figure 10-7 Example SXP Peer Connections

The following example shows how to configure the SXP peer connections on SwitchA:

feature cts

cts role-based enforcement

cts sxp enable

cts sxp connection peer 10.20.2.2 password required A2BsxpPW mode listener

cts sxp connection peer 10.30.3.3 password required A2CsxpPW mode listener

The following example shows how to configure the SXP peer connection on SwitchB:

feature cts

cts role-based enforcement

cts sxp enable

cts sxp connection peer 10.10.1.1 password required A2BsxpPW mode speaker

The following example shows how to configure the SXP peer connection on SwitchC:

feature cts

cts role-based enforcement

cts sxp enable

cts sxp connection peer 10.10.1.1 password required A2CsxpPW mode speaker

Default Settings

Table 10-1 lists the default settings for Cisco TrustSec parameters.

Additional References

For additional information related to implementing Cisco TrustSec, see the following sections:

•Related Documents

Related Documents

Feature History for Cisco TrustSec

Table 10-2 lists the release history for this feature.