Dummer's tenure as acting governor has been described by historian John Ragle as "unspectacular but able".
 In the first half of 1723 Dummer made concerted efforts to recruit the Iroquois (of what is now upstate New York) as allies against the Abenaki, and sought to avoid the participation of bands of western Abenaki (based in what is now Vermont) in the conflict.
 In both of these he was unsuccessful: the Iroquois, despite significant financial inducements, refused to take up arms against tribes seen to be allied with New France, or to engage in a conflict in which they had no stake.
 The Massachusetts embassy to Grey Lock, the principal leader of the western Abenakis, failed to find him.

In August 1723 Grey Lock began raiding Massachusetts frontier communities in the Connecticut River valley, taking captives and inflicting casualties at Northfield.
 Dummer appealed to the leaders of the Connecticut Colony, who stationed a company of militia there in December to little effect.
 He also authorized construction of a fort north of Northfield, on land he had acquired a few years before in Connecticut's auction of the so-called "Equivalent Lands" Massachusetts gave to Connecticut as compensation for border issues.
 The stockaded fort was located in what is now Brattleboro, Vermont, and was named Fort Dummer in his honor.
 It is regarded as the start of permanent European settlement in the modern state of Vermont.

Fort Dummer was ineffective at stopping the Indian raids.
When Grey Lock's raids continued unabated in 1724, Dummer renewed his appeals to Connecticut Governor Gurdon Saltonstall, noting that Connecticut was equally vulnerable to raiding should the Massachusetts towns in the Connecticut River be abandoned.
 Saltonstall sent further reinforcements, but Abenaki raids in the area continued until 1727, when Grey Lock apparently tired of continuing the war without outside support.
 Embassies sent by Indian commissioners in Albany, New York and by eastern Abenaki leaders failed to make contact with the warrior, and he disappeared from view.
Dummer's tenure as acting governor has been described by historian John Ragle as "unspectacular but able".  In the first half of 1723 Dummer made concerted efforts to recruit the Iroquois (of what is now upstate New York) as allies against the Abenaki, and sought to avoid the participation of bands of western Abenaki (based in what is now Vermont) in the conflict.  In both of these he was unsuccessful: the Iroquois, despite significant financial inducements, refused to take up arms against tribes seen to be allied with New France, or to engage in a conflict in which they had no stake.  The Massachusetts embassy to Grey Lock, the principal leader of the western Abenakis, failed to find him.
In August 1723 Grey Lock began raiding Massachusetts frontier communities in the Connecticut River valley, taking captives and inflicting casualties at Northfield.  Dummer appealed to the leaders of the Connecticut Colony, who stationed a company of militia there in December to little effect.  He also authorized construction of a fort north of Northfield, on land he had acquired a few years before in Connecticut's auction of the so-called "Equivalent Lands" Massachusetts gave to Connecticut as compensation for border issues.  The stockaded fort was located in what is now Brattleboro, Vermont, and was named Fort Dummer in his honor.  It is regarded as the start of permanent European settlement in the modern state of Vermont.
Fort Dummer was ineffective at stopping the Indian raids. When Grey Lock's raids continued unabated in 1724, Dummer renewed his appeals to Connecticut Governor Gurdon Saltonstall, noting that Connecticut was equally vulnerable to raiding should the Massachusetts towns in the Connecticut River be abandoned.  Saltonstall sent further reinforcements, but Abenaki raids in the area continued until 1727, when Grey Lock apparently tired of continuing the war without outside support.  Embassies sent by Indian commissioners in Albany, New York and by eastern Abenaki leaders failed to make contact with the warrior, and he disappeared from view.
William Dummer