My point is that no matter how good a job the DAC does in cleaning up the signal it receives, and no matter how good the design of the DAC may be, signals and noise don’t necessarily just affect or entirely follow only their intended pathway. And the waveform characteristics and the noise characteristics of the signal that enters the DAC will affect how and if RF energy present in that signal may to at least a small degree find its way via unintended pathways to unintended circuit points "downstream" of the ethernet interface and the internal reclocker you referred to.
Very true, however I would avoid the term "RF". Its mostly what is referred to as "conducted" interference. In the case of Ethernet, it is leakage across the transformer interface. In most cases RFI is a result of ground-loops.
If you have wired Ethernet to your DAC and you are using a cheap Chinese LPS or a Sbooster, make sure that the DC common is tied to the earth ground one way or another.
Steve N.
Empirical Audio