What port is used for PostgreSQL backup?

The proper port used for PostgreSQL is 5432, which is the default port for database connections. However, in your options, the closest relevant choice is 5433, which is often used by PostgreSQL for an alternate instance or configuration.

The reason 5433 is appropriate in certain contexts is that during installations, users can opt to run multiple instances of PostgreSQL on a single machine, with the second instance typically using port 5433.

The other ports listed in the question are not standard ports associated with PostgreSQL:

• 8061 and 8081 are generally associated with web servers or application servers.

• 27001 does not correspond to typical database services.

It's important to understand the context and configurations of PostgreSQL when discussing ports, as well as the ability to set up multiple instances, which clarifies the relevance of port 5433 in this situation.