"but cisco state nbar is not support for the 3750."
I believe that to be correct.
NBAR isn't generally supported on Cisco L3 switches but with a couple of exceptions. I believe a couple of WAN boards for the 6500/7600 support it (e.g. FlexWAN), and the sup32-PISA supports (I think) something similar with FPM.
As Joseph stated NBAR is not supported on the 3750. The 3750 does not have the hardware to support NBAR. The only switch that is able to support NBAR is the 6500. This is typically a function that is ran on a router not on a switch.
External packet analyzers are popular, especially the free WireShark. If the 3750 supports SPAN, you can then examine the traffic crossing a port of interest. (Analysis capabilites are also much more extensive than one NBAR provides.)
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