Use Case

As a Node.js Driver user
I want the driver to attempt to use all A and AAAA records for each hostname
So that the driver automatically handles connecting to exclusively IPv4 or exclusively IPv6 bound servers without needing configuration changes.

User Impact

• Users will be able to connect to servers bound to IPv4 or 6 or both addresses
• Driver will prefer IPv6 addresses

Dependencies

• The driver will own DNS lookup steps prior to socket creation

Unknowns

• How does this impact unix socket usage? Does a driver continue to use unix sockets?
• Should connectTimeoutMS and/or CSOT control how long we wait for DNS to resolve?
• What logging if any should be included before/after lookup?

Acceptance Criteria

Implementation Requirements

• Hostnames should be resolved to AAAA and A records
• The driver should prefer connecting to IPv6 addresses, but attempt all

Testing Requirements

• Remove all DNS resolution order settings
• Ensure that localhost resolving to ipv6 and v4 work (can use sinon for this)

Documentation Requirements

• Remove note about handling for IPv4/6 from readme

Follow Up Requirements

• None.