Schools that had often welcomed parents and visitors with open front doors locked them Monday as several Boston-area superintendents said they planned to reconsider their safety protocols or accelerate plans to install buzzers and cameras in response to the mass shooting at a Connecticut elementary school.

In suburban communities such as Hingham, Wellesley, Natick, Winchester, Medford, and Weston, the desire to reassure anxious parents and students won out over the traditional treatment of school buildings as open community centers. Boston schools also stepped up security.