An open Internet port is a vulerability. Most server installations default to running many more network services than is necessary for website and email service.

For security reasons, I cannot list all the network services our servers provide. However, for the unix savy, here is a count:

netstat -an | grep LIST | awk '{print $4}' | awk '{FS=":"}{print $2}' | sort | uniq | wc -l
= 14

I am very cautious with the services I allow to be exposed to the Internet. Let me know if you would like to know more details.