I covered my Netgear switch and plug in 3M EMI/RFI shielding absorber, used the filters below on the ethernet cable and put a choke of on the cord from the wall wart.
DX Engineering DXE-ISO-PLUS-2 - DX Engineering ISO-PLUS Ethernet RF Filters
Ethernet EMI Filter, Patent Pending, RF Common Mode Choke, Inline Coupler EMI Filter, GbE, Double Female RJ-45, Cat 5e, Cat 6 Compatible, Pair.
I had the choke and absorber paper left over from another project.