SMTP settings, lets you customize your SMTP service settings through the WebAdmin interface. It allows you to configure the following:
- This allows users to authenticate directly with the SMTP server via their mailclient
- This option adds the IPs of users authenticating via POP3/IMAP to the MailRelay table, allowing them to authenticate with the SMTP server successfully
- This will set the maximum amount of concurrent connections to your mailserver. This can prevent denial-of-server attacks
- Sets the maximum amount of connections via IP. This prevents the overloading of the SMTP service
- Sets the maximum number of recipients an IP address can send to. This can prevent users from using your mail service for spamming
- Checks that the sender of a message sent to the system has a valid MX/Record.
- The load-average that the @Mail server can handle before it rejects further SMTP connections
- The load-average that the @Mail server can handle before placing further emails in the queue
- The load average that the @Mail server can handle before it stops processing emails in the queue
- Slows down mail-delivery when a user attempts to send a message to a massive number of recipients
- This value specifies the maximum number of processes that handle inbound and outbound mail. This only applies to concurrent instances of Exim.
- This setting specifies the maximum number of destinations that outbound mail can be delivered to, simultaneously.
- When turned on, this sets Exim to scan the mail queue sequentially, rather than randomly. We recommend that this setting be turned on, only in large implementations of @Mail.
- For large installations with over 10,000+ users the Exim spool directory can be split into 62 subdirectories - prefixed by uppercase and lowercase alphanumeric characters and digits. This is used to increase the performance for installations that have a large number of messages in the mail-queue. Linux filesystems suffer a massive performance hit when more than 10,000 files are in a single directory - this helps alleviate that load.
- This setting enables Exim to enforce SMTP synchronization, if a remote client sends data before the SMTP banner out of of sync, the connection is automatically dropped. This feature is used to avoid zombie Spammer connections and non RFC compliant connections to the mail-server.