sendmail and NOQUEUE: Null connection from root@localhost in log files

We were alerted to some of these messages in the log files and found a page where some CERT folks described discovering a root hack on their box and these messages in the log files. None of their other symptoms seems present on my box, though I do have a decent number of these NOQUEUE messages,

sendmail and NOQUEUE: Null connection from root@localhost in log files

We were alerted to some of these messages in the log files and found a page where some CERT folks described discovering a root hack on their box and these messages in the log files. None of their other symptoms seems present on my box, though I do have a decent number of these NOQUEUE messages, so