Device Access Policy Overview
Starting from Cisco SD-WAN Release 19.3, the Cisco SD-WAN Manager user interface is enhanced to configure device access policy on all the Cisco Catalyst SD-WAN devices.
The control plane of Cisco vEdge devices process the data traffic for local services like, SSH and SNMP, from a set of sources. It is important to protect the CPU from device access traffic by applying the filter to avoid malicious traffic.
Access policies define the rules that traffic must meet to pass through an interface. When you define rules for incoming traffic, they are applied to the traffic before any other policies are applied. You can use access policies, in routed and transparent firewall mode to control IP traffic. An access rule permits or denies traffic based on the protocol used, the source and destination IP address or network, and optionally, the users and user groups. Each incoming packet at an interface is analyzed to determine if it must be forwarded or dropped based on criteria you specify. If you define access rules for the outgoing traffic, packets are also analyzed before they are allowed to leave an interface. Access policies are applied in order. That is, when the device compares a packet to the rules, it searches from top to bottom in the access policies list, and applies the policy for the first matched rule, ignoring all subsequent rules (even if a later rule is a better match). Thus, you should place specific rules above more general rules to ensure the specific rules are not skipped.