In Cisco networking, configuring the correct Server Address is crucial for successful authentication, authorization, and accounting (AAA) processes. This configuration is particularly vital when utilizing external authentication servers like TACACS+ and RADIUS. Let’s examine a sample configuration from a Cisco 9300 series switch to understand how server addresses are defined and grouped within the AAA framework.
The provided configuration snippet outlines the AAA setup on a Cisco Cat9k switch, emphasizing the role of server addresses in directing authentication requests. We observe several key components, starting with the definition of authentication methods for different access types, such as login and enable access. These methods specify the use of local databases and external server groups like dnac-network-tacacs-group and ISE_TACACS. The server address is not directly visible here, but these groups act as pointers to where the actual server addresses are configured.
Moving into the group definitions, we see aaa group server tacacs+ dnac-network-tacacs-group and aaa group server tacacs+ ISE_TACACS. Within these group configurations, the server address becomes explicitly defined using server name commands. For instance, server name dnac-tacacs_x.x.x.x and server name ISE-PSN-1 indicate the logical names assigned to specific server addresses. These names then resolve to actual IP addresses, configured under the tacacs-server section.
Finally, the tacacs-server section is where the physical server address is configured. Commands like tacacs server dnac-tacacs_x.x.x.x address ipv4 x.x.x.x and tacacs server ISE-PSN-1 address ipv4 x.x.x.x directly associate the server names with their IPv4 addresses. Additional parameters like key and timeout are also configured here, enhancing security and connection management. It’s evident that the correct server address configuration at this level is fundamental for the switch to communicate with the designated TACACS+ or RADIUS servers for AAA functions. Issues with connectivity to servers like ISE-PSN-1 and ISE-PSN-2, as highlighted in the original text, often stem from misconfigurations or reachability problems related to these defined server addresses.
