Sundar gave you a good answer about how to enable NetFlow on an IOS based box. The procedure to enable it if your layer 3 switch runs in hybrid mode is slightly different.
Also you asked if there is need for some server to process NetFlow. I believe that the answer to that question depends on what you are trying to accomplish. As Sundar has shown there are CLI commands to show the NetFlow records (which get tricky to interpret as the traffic volume increases, and the flow records have a very limited lifetime on the device that generates them). So most people who run NetFlow do export the NetFlow records to some external device (server) which will accumulate the NetFlow records and assist in interpreting them. So is an external server required? Not necessarily - but most people do have an external server.
netflow is not supported on the 3550 series. You can use netflow on: 800, 1400, 1600, 1700, 1800, 2500/2600, 2800, 3600, 3800, 4500/4700, AS5300/5800, 7200/7500, 4500, 5000, 6500, 7600, 10000, 12000 and CRS-1. If you want to know more about netflow visit netflow software web page: http://netflow.caligare.com There is also list of known netflow analyzing applications and developers.
In the table 1 there is that Cisco doesn't support netflow on the 2900, 3500, 3660 and 3750 series. I know that netflow works on the 3550 switches with older IOS, but in the exports there wasn't all flows, only the first routed packet (other packets that were switched, were not stored in the netflow cache).
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
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