Security is top of mind for most companies today. And for good reasons. Every day new major security incidents hit both the private and public sectors. We’re no longer dealing with curious geeks, script kiddies, and smaller groups of cyber criminals. Hacking used to be a niche thing. Today state-sponsored hackers are a reality.

Although you cannot guarantee protection from these malicious events, you can try to limit the risk and possibility of their success. Various methods and technologies help narrowing the attack surfaces you make available to the threat actors.

DNAC is currently not designed to be VRF-aware with its Network Settings. The AAA server settings are configured with global context regardless of the device management IP being in a VRF.

Here is what DNAC provisions for RADIUS:

aaa new-model
aaa authentication login default local
aaa authentication login dnac-cts-list group dnac-client-radius-group local
aaa authentication dot1x default group dnac-client-radius-group
aaa authorization exec default local
aaa authorization network default group dnac-client-radius-group
aaa authorization network dnac-cts-list group dnac-client-radius-group
aaa accounting Identity default start-stop group dnac-client-radius-group
aaa accounting update newinfo periodic 2880
!
aaa server radius dynamic-author
 client 10.0.0.111 server-key <secret>
 client 10.0.0.112 server-key <secret>
!         
radius server dnac-radius_10.0.0.111
 address ipv4 10.0.0.111 auth-port 1812 acct-port 1813
 timeout 4
 retransmit 3
 automate-tester username dummy ignore-acct-port probe-on
 pac key <secret>
!
radius server dnac-radius_10.0.0.112
 address ipv4 10.0.0.112 auth-port 1812 acct-port 1813
 timeout 4
 retransmit 3
 automate-tester username dummy ignore-acct-port probe-on
 pac key <secret>
!
radius-server attribute 6 on-for-login-auth
radius-server attribute 6 support-multiple
radius-server attribute 8 include-in-access-req
radius-server attribute 25 access-request include
radius-server attribute 31 mac format ietf upper-case
radius-server attribute 31 send nas-port-detail mac-only
radius-server dead-criteria time 5 tries 3
radius-server deadtime 3
!
aaa group server radius dnac-client-radius-group
 server name dnac-radius_10.0.0.111
 server name dnac-radius_10.0.0.112
 ip radius source-interface Loopback0
!
ip radius source-interface Loopback0

Here my ISE PSNs are 10.0.0.111 and .112

In this post I will show you some examples of Jinja templates that might inspire you to create your own. As always my focus is centered on how stuff works rather than how you use the product. I will provide a breif overview of the Template Editor, though. For a user guide, please have a look at the official doc: Create Templates to Automate Device Configuration Changes

One of the main advantages of DNAC is its ability to help you automate certain tasks within your network. One of which is configuration changes. Here DNAC will ensure consistent configuration pushes to your devices while bringing automation capabilities to the table.

DNA Center has a versioning scheme that uses four digits. At the time of writing the recommended DNAC version is 2.2.3.6

 2.b.c.d - The first digit is the major release which introduces “significat market value, including infrastructure and architectural changes”
 a.2.c.d - The second digit is a minor version that includes “new functions and features in the platform”. It is categorized as a “new market value” release and also an anchor point for long-lived releases
 a.b.3.d - Third digit represents “new functions in applications” and it is categorized as a “minor-minor” release
 a.b.c.6 - Fouth digit is the patch level. You should only see bug fixes for these releases, but Cisco states that you could see “enhancements to existing functions introduced in a previous feature release”, which i interpret as enhancements from a “minor-minor” release

If you are looking to configure NIC bonding for DNAC, this post will show the currently available options for the DN2-HW-APL appliance running DNAC version 2.2.2.6 and newer. Only 10G interfaces are addressed for NIC bonding in this post. If you want to play with 1G interface NIC bonding, have a look at the official documentation

NOTE! NIC bonding is not supported for the DN1-HW-APL (1st gen DNAC appliance). An apparent reason for this is that the DN1 appliance only comes with a single NIC adapter with two 10G interfaces. Cisco wants the NIC bonding to be configured on two different physical NIC adapters.

The Challenge

Operating a network can be a daunting task. Especially when you find yourself manually repeating ordinary work on a regular basis. As a network engineer you are likely to enjoy challenges with protocols and designs rather than unboxing, mounting, and installing hardware. The time spent on this everyday work should be kept at a minimum. In a streamlined network design, the configuration of new equipment should be based on a template with few variables, such as hostname and IP addressing. Many companies already practice using templates, but for the most part the engineer must still manually adjust these variables, or at best some advanced excel spreadsheet or flat text file is used with a manual search and replace to build new configurations. Next, the device is powered up, connected to with a console cable and the newly build configuration is pasted into the device before installing it in its final location. Oh, and now both software upgrade and licensing tasks must be performed to be compliant. The workflow is manual, time consuming, and worst of all error prone due to the inevitable human factor.

Unfortunately not all Cisco platforms support SDA. Cisco has chosen these platforms to be extended by SDA to be able to offer both a desktop platform and IoT platforms:

• 3560CX
• IE 3300
• IE 3400
• IE 3400H
• IE 4000 series
• IE 5000 series
• Catalyst Digital Building

NOTE! If you plan on using policy, meaning micro segmentation using SGTs, only IE 3400 and IE 3400H are supported as policy extended nodes!

Extended nodes must be connected to a single (or stacked) edge switch (excluding Catalyst 9200).

Some companies are established with multiple sites in a small geographic area inter-connected with DWDM, dark fiber, or maybe MPLS. SDA transit could make sense to configure if the MTU (>= 1550 bytes) and latency (~10 ms) allows for it. One advantage of using SDA transit is the end-to-end VXLAN encapsulation which menas we have end-to-end policy for both macro (VN) and micro (SGT) segmentation when using SDA transit.

In this post I’ll go over how you could go about configuring direct internet access (DIA) using SDA transit. Along the way I’ll show how it works and why.

In this post I’m using DNAC version 1.3.3.3 for demonstrate what happens when you discover a switch using DNAC.

Previously I’ve written similar posts:

DNA Center - PnP - What It Does To Your Devices DNA Center - Provision - What It Does To Your Devices

Test Case

One simple test case is all we need to see what DNAC does:

• Manually configure a Cat9300 switch
• Add the switch to DNAC using a discovery job

Topology

The below topology is used for this post:

In this post I’m using DNAC version 1.3.3.3 to demonstrate what DNAC does to your device when configuring the network settings in DNAC.

Previously I’ve written similar posts:

DNA Center - PnP - What It Does To Your Devices DNA Center - Discovery - What It Does To Your Devices

Test Case

One simple test case is all we need to see what DNAC does:

• Manually configure a Catalyst 9300 switch
• Add the switch to DNAC manually via inventory

Topology

The below topology is used for this post: