Yes, it can. Since you are using dsl, I suppose you are using it through PPPoE, so here is your problem https://en.wikipedia.org/wiki/Point-to-point_protocol_over_Ethernet#MTU.2FMRU I had the same problems (but on OpenBSD router). On Debian it can be circumvented by using pppoeconf. It is by default settings your connection with appropriate MTU
in the router config I see I'm connected by pppoeconf: mtu: 1400 mrt: 1492 so I've setted mtu of interface card to 1492 same problem... thanks! -- Pol