| MTA Options | |
| [Default Domain] | On client agent, it is considered belonging to this domain when sender address does not contain Domain. |
| [Monitor IP] | Monitor IP by MTA. |
| [Security Limit] | The max connections and frequency of one client. |
| [Processes Limit] | The default processes when starting MTA. |
| [Max Message Size] | The max message size of sending by MTA. |
| [Authentication] | Authentication related options. |