The review for Kent Police backed its decision not to ban a march by far-right groups on 30 January and how the force responded.
Several people were injured as rival groups threw bricks and bottles.
Charlie Elphicke, Conservative MP for Dover and Deal, said two opposing demonstrations should not have been allowed at the same time.
He tweeted the review was a "whitewash".
Far-right marchers included the North West National Front, Combat 18 and the Scottish Defence League.
Counter-demonstrators included Kent Anti-Racism Network, Antifa and people with Socialist Worker placards.
The two sides met head-on in the town centre and earlier at a motorway services, despite police efforts to keep them apart.
Police said nearly 40 people in total have been arrested, 17 on the day. Charges have been brought against 16 people, six of them for violent disorder.
The National Police Coordination Centre (NPCC), which advises on major disorder, carried out a review for Kent's Chief Constable Alan Pughsley.
It concluded "any attempt to ban or impose conditions" on the anti-immigration march "would have been inappropriate" and "a significant policing operation would still have been needed".
The NPCC found "a considerable amount of planning" with "nearly 400 officers and staff to mitigate the risks".  It said resources were "adequate", tactics were "appropriate" but some areas could be improved, such as greater command resilience.
Kent's Police and Crime Commissioner, Ann Barnes, said the review validated the force for doing "a good job in extremely difficult circumstances" and the "restraint and professionalism shown is to be commended".
The policing of immigration protests in Dover was "justifiable" and "entirely appropriate", a report has found.