Open Relay Problems

I have a SuSE 7.3 Sendmail host running Sendmail v8.11 function as my Primary MX. Someone is spamming mail into my domain. This host does not have any accounts on it, just an aliases file. How can I stop this?? Shonne Beavers shonnedb@directvinternet.com ICQ 138341211 "In order to accomplish good, we must compromise some of the evils of this world." --Unknown