Vectoring very high speed digital subscriber line 2 (VDSL2) lines will coexist with legacy VDSL2 lines during copper access network migration. Without the ability of legacy lines to cooperate for crosstalk channel estimation, Vectoring lines may still suffer from crosstalk noise. We study the spectral protection of Vectoring lines by dynamic upstream power back-off (UPBO) and provide a multiobjective methodology for fairness optimization between legacy and Vectoring lines. Extensive simulation and exemplary testbed results with up to 20 lines illustrate the tradeoff in mean-rate offered to network operators, as well as the effect of various fairness definitions.