In troubleshooting a network problem recently, I was reminded about a feature set which is turned on by default on their Small Business and Catalyst Express Switches called Smartports Roles, and in their larger switches and routers they are called Smartport Macros (but are not enabled by default and used in the CLI). This is a love-it or hate-it feature of Cisco SMB switches. When we think of managed switches, how much feature set are we often using other than VLAN, QoS and perhaps high-throughput? The reality is that managed switches have a lot more feature and functionality to them which we often don’t configure. Cisco had made these feature also available as templates for small businesses. Which is great, unless you don’t realize they’re in-place. If you don’t know about Smartport rules you can spend hours chasing your tail.
The biggest gotcha you need to know is that by default most ports are configured in the “Desktop” role, which permits only one Mac address per port, and it disables spanning tree to permit fast network connectivity. If you connect in a switch you may notice that only the first node will actually work, and all others will fail to connect (this is port security).
In those cases you want “Switch” mode which permits multiple IPs (disabled port security) and enabled Rapid Spanning Tree (RSTP). Continue reading “Cisco Smartports”
