You are the network administrator of a medium-sized company， and users are complaining that they cannot send emails to some organizations. During your troubleshooting， you notice that your DNS MX record is blacklisted by several public blacklist filters. After clearing these listings for your IP address， and assuming that your email server has the right virus protection in place， what are two possible solutions to prevent this from happening in the future？（）

A. Change your Internet provider.
B. Change your public IP address.
C. Allow the email server to send traffic only to TCP port 25.
D. Put your email server in a DM
E. Use a separate public IP address for your email server only.