1 | initial version |
If I understand it correctly you have a (wired) Ethernet cable between the modem and the Linksys Mesh router and the modem is truly a modem (not doing routing, firewalling, NAT, etc.). Then capturing on the WAN side is basically the same as on the LAN side.
A tap will work.
A switch with monitor function will also work, provided the ISP does not check for or require specific MAC-addresses. Depending on the model of the switch you may have to disable the 'packet injection' feature.