It's not just connect based, you have to connect and send an email. Which would be spam. Most systems I've worked on score based on how much your server looks

It's not just connect based, you have to connect and send an email. Which would be spam. Most systems I've worked on score based on how much your server looks like it's doing its job and moving on. Long connection with inactivity get tagged, scored and disconnected. Connecting without sending an email leaves you in the grey list queue. There is to my knowledge not a great way to pre-warm for grey-listing