Ferrite Cores

Do ferrite cores make a difference or do harm on Ethernet connections/cables?
One came with my PS Audio DMP and I seem to remember it should be placed close to the DMP.
I ask because I have pack of them.
Using Blue Jeans Cables 6a. Where if anywhere should they be placed?
Any insight would be helpful.

it this shielded or unshielded ethernet cable?

Believe it is shielded, but to be honest I don’t know.

if unshielded don’t bother. If shielded I put one at each end and one two thirds or three quarters of the way along. This is not especially scientifically based, and I didn’t notice any difference.

Nearly all 6A are shielded and nearly all 6 are not. Unlikely the ferrite cores will make any difference but they won’t ‘hurt’ the cable and likely won’t affect the sound.

If you have a ton of RF in the range the ferrite is designed to attenuate and your DAC is fed by Ethernet and it’s highly susceptible to RF in the range the ferrite reduces you may notice a difference but unlikely all these forces will match up perfectly.