Archer C2 v3 -> mělo by to být Security -> Settings -> odškrtnout "Ignore Ping packet from WAN port"
BTW, máš v1 nebo v3?
http://static.tp-link.com/resources/simulator/Arch er_C2/index.htm
http://static.tp-link.com/resources/simulator/Arch erC2v3(UN)_Emulator/index.html