Ethernet

Switch. 

... and or use a gas discharge tube outside if coaxial.

(1) Quality build and superior shielded Ethernet cable long enough single cable from the internet router to the network switch positioned close to your audio system ….say, within a metre away from the audio. equipment.

(2) You don’t need to go hog wild yet on an expensive “audiophile rated “ esoteric network switch expensive model ( think Silent Angel et al ). The latter custom units do work very well as audio performance upgrade for sure, but they are ka-Ching $$$$. I use a modest “ normal “ ( CISCO or peer grade home ….) 4-port Ethernet netwitk switch BUT ….and its a big “ but” ,with an upgraded 3rd party external power supply … go get an iFI POWER X.. Now the audio performance step-up results were immediate and a significant chunk the audiophile grade switch added audio performance, but at a fraction of the audiophile grade network switch price,

(3) Then you can plug in up to four shorter, - say 1m length - quality build Ethernet shielded Ethernet now cables into the four network switch ports

(4) the other end of the Ethernet cables are then connected to your Ethernet connected sources , ….player, NAS, streamer , DAC etc.

EZPZ

If you going to buy a switch they $20 make a ton of noise as well as your router .

this switch is the best value for all it offers and under $600. LHY SW-8
and on your router most are 12 v and around  4 amp

i spent a bit more from Linear Tube Audio they make a great Linear power supply up to 20 v  and 8 amp capable , $750  for your router little green computer $299

get rid of those horrible $5 wall warts they destroy the fidelity especially if streaming.

I second all of the suggestions here, including the one about changing the router, but I use a basic Linksys switch that has 10 ports and have had no issues.  I had looked at an uber$ Melco switch, since I use a Melco NAS/Player, but decided that the $1500 price tag wasn’t justifiable, especially since that is about 15 times more expensive than the router