Do you mean behind the ISP modem, or are you looking at the direction in reverse? I’ve always used “in front” to mean between the wall and the modem. This is ty

Do you mean behind the ISP modem, or are you looking at the direction in reverse? I’ve always used “in front” to mean between the wall and the modem. This is typically not possible because many providers in the US—e.g., AT&T—expect their box to be first from the wall with certs that authenticate a connection to their network. Thus, using a router that’s under your control requires placing it after the ISP’s modem/gateway (which always meant behind to me).