Configuring the firewall to deny all traffic by default and allow only necessary services based on the principle of least privilege makes the network more secure. This practice ensures that only the minimal necessary services and connections are permitted, reducing the attack surface. Implementing an implicit allow rule can be dangerous as it may unintentionally permit unwanted and potentially harmful traffic. Allowing all outbound traffic is not a security best practice since it can allow infected systems to communicate with external command and control servers, or exfiltrate sensitive data. An allow-all rule with logging for troubleshooting purposes is not secure, as the network would be exposed while troubleshooting is carried out, potentially allowing for exploitation or unauthorized access.