The Bluebirds struck twice just before half-time. First, Liam Hughes's header was adjudged to have crossed the line, despite the valiant attempts of Jordan Maguire-Drew to clear.
Byron Harrison then tapped in his 15th goal of the season on the break.
The sides exchanged quick goals after the break. Richie Bennett volleyed into the top corner for Paul Cox's men, before Corey Whitely converted on the rebound for Dagenham after Tim Erlandsson had saved Luke Guttridge's initial effort.
Harrison extended the away side's lead from the spot after Moussa Diarra had been baulked in the box.
Report supplied by the Press Association.
Match ends, Dagenham and Redbridge 1, Barrow 4.
Second Half ends, Dagenham and Redbridge 1, Barrow 4.
Substitution, Barrow. Lindon Meikle replaces Jordan Williams.
Substitution, Barrow. Ross Hannah replaces Byron Harrison.
Substitution, Dagenham and Redbridge. Tyrique Hyde replaces Scott Heard.
Substitution, Dagenham and Redbridge. Paul Benson replaces Oliver Hawkins.
Goal!  Dagenham and Redbridge 1, Barrow 4. Byron Harrison (Barrow) converts the penalty with a.
Substitution, Dagenham and Redbridge. Christian Assombalonga replaces Jimmy Shephard.
Goal!  Dagenham and Redbridge 1, Barrow 3. Corey Whitely (Dagenham and Redbridge).
Goal!  Dagenham and Redbridge 0, Barrow 3. Richard Bennett (Barrow).
Jordan Williams (Barrow) is shown the yellow card for a bad foul.
Tim Erlandsson (Barrow) is shown the yellow card for a bad foul.
Second Half begins Dagenham and Redbridge 0, Barrow 2.
First Half ends, Dagenham and Redbridge 0, Barrow 2.
Goal!  Dagenham and Redbridge 0, Barrow 2. Byron Harrison (Barrow).
Goal!  Dagenham and Redbridge 0, Barrow 1. Liam Hughes (Barrow).
First Half begins.
Lineups are announced and players are warming up.
Barrow took their astounding unbeaten run to 20 matches in all competitions with a significant win at promotion rivals Dagenham.