Global size limits can be set for incoming mail. These limits are used to keep messages that are too large off of the server.
If you would like to edit the size limits, click the Edit button.
There are two different mail protocols that SLmail “speaks.” Simple Mail Transfer Protocol (SMTP) is the more common of the two and is supported by the majority of email clients and mail servers. When a message is received by SLmail it checks for the size specified in SMTP. If the message is larger than the maximum allowable size, the message is dropped and a 500 level (fatal) error message is sent back to the originating server.
If you would like to enable the SMTP size limit, select the Limit All Inbound SMTP check box and then click the Next button.
The second is Extended Simple Mail Transfer Protocol (ESMTP) and it is by the SLmail server to signify to other mail servers (that understand it) the maximum message size allowed. When a connection is made, SLmail sends a message to the sending server that contains the ESMTP size limit. If the sending server understands ESMTP and the message is larger than the maximum allowed by SLmail, then the message is not sent. If the sending server does not “speak” ESMTP then this message is disregarded and SLmail relies on the SMTP size.
SLmail limits inbound messages using ESMTP size by default. If you would like to disable this limit, uncheck the Limit All Inbound ESMTP check box and click Next .
You must specify the maximum size of message that you wish to accept with SLmail.
Enter the maximum size in bytes that you would like to accept. This limit applies to both SMTP and ESMTP. After the limit has been entered, click the Next button.
You will be asked to confirm the changes made in the SMTP Size limits by clicking the Apply button on the next dialog box.