Carl Piergianni headed United into a 55th minute lead following Kyle Dixon's free-kick, but Town levelled 10 minutes later through Jack Frohawk.
Mark Jones had seen a goal ruled out for offside in the first half for a United side missing a handful of players with knocks and niggles.
Boston (4-4-2): Matt Urwin (Alex Brown 73); Jake Sheridan (Cameron Dear 49), Zak Mills (Dymon Labonne 66), Carl Piergianni, Julian Bennett; Kaine Felix, Scott Garner, Kyle Dixon, Jay Rollins (Harry Limb 77); Mark Jones, Jack Smith (Jamie McGhee 49).
Referee: Alistair Wilson.
Attendance: 356.