There are several features that can be enabled or disabled in the Options Page.
These features are mirrored in the SLmail Control Panel Applet on the Options tab.
Highlight the option in the list and a description of the option is displayed in the window. If the option is configurable (other than on or off) the Details button is enabled. Click the Details button to make changes to the option and then confirm the changes by clicking the OK button.
Note: The Slmail service must be stopped and restarted in order for any changes made in the options tab of the Control Panel Applet to take effect.
If a size limit has been imposed by the Use Extended Simple Mail Transfer Protocol (ESMTP) Size option (as seen in the previous illustration), the Broadcast ESMTP Size option will tell other mail hosts what the maximum size is. The remote mail host will then know that an oversized piece of mail will be rejected, and therefore will not transmit it. If this option is disabled, SLmail will not inform other mail hosts of a maximum size.
Note: This option requires that both the Use ESMTP Protocol option and the Use ESMTP Size option be enabled.
This option affects the method SLmail uses to search for addresses. If SLmail is unable to find an MX record or an actual address for a given address, it is possible that the computer exists on a subnet that is only accessible through a gateway. If this occurs, and if the Check for Mail Subnets option is enabled, SLmail will check for subsets of the node name, removing the leftmost part of the node name and working right until there is no more node names left. If this option is disabled, SLmail will try only the original node name. By default, this option is enabled.
Normally, the Name Server specified in the Name Server field of the System page provides Domain Name Service lookup. There may be conditions in which you do not want the Name Server to perform DNS lookup. You might, for example, be sending through a Smarthost or setup for an Intranet only.
If the Disable MX Lookup option is checked, no DNS lookup is performed, and SLmail depends on the IP stack's built-in name service resolution. By default, this option is unchecked and DNS lookups will be performed. Unless you are confident with what you are doing, don't alter the defaults of this setting.
Internet mail servers can make use of another mail host to resolve mail addresses they themselves cannot resolve. This other host is called the Smart Host. For large networks, your Smart Host may be a more central computer, but for most SLmail sites, the Smarthost is probably the mail server at your ISP.
It is possible, however, to use SLmail without a Smart Host, for example, when SLmail is on a dedicated Internet connection. If this option is enabled (checked), any mail that cannot be resolved using the DNS server will be bounced back to the user who sent the message. By default, this option is enabled (checked) and mail that cannot be resolved locally is bounced back to the original sender.
Note: When SLmail is configured for a dedicated connection Disable MX Lookup is normally unchecked and Disable Smart Host is checked. When SLmail is configured for a Dialup connection, Disable MX Lookup is normally checked and Disable Smart Host is unchecked.
If this option is enabled, SLmail allows remote nodes with which SLmail exchanges mail to use the SMTP EXPN and VRFY commands. The Expand (EXPN) command allows the remote node to determine who the recipients are on a given mailing list. The Verify (VRFY) command allows the remote node to see whether a specified user exists on the system. If this option is disabled, SLmail does not divulge this information to remote nodes that might request it. By default, this option is enabled.
If this option is enabled, SLmail will require that any incoming connections from clients or other servers speak ESMTP and not SMTP.
Note: To enable this option, you must also enable the Use ESMTP Protocol option.
If this option is enabled and a partial message is received, SLmail generates a short message to inform the sender that only part of the message has been received. Enabling this option is appropriate for a site plagued by noisy or dropping lines, where users need to know that line conditions are currently impeding the flow of mail. By default, this option is disabled.
Normally, when you submit a send-file message to the autoresponder (AR), the autoresponder will generate a report back with the text of your mail and comments underneath each command showing the results. Most of these results will show normal conditions, such as "end of commands" or "this file is sent." You may only wish to suppress these reports of normal conditions and only get a report if there is at least one result that is not an "end of commands" or "this file is sent." Enabling the Only Send Bad AR Replies option will do so. By default, this option is disabled and all results are reported.
If this option is enabled, all mail for unknown users is rerouted to the alias "unknown." This alias can then be set to point to any local account.
For example, if the unknown alias on your system domain.com is set to point to root and you received mail for former_employee@domain.com , (and former_employee was not a valid account) the mail would be rerouted to root. If this option is disabled, the mail to former_employee is bounced back to sender. By default, this option is disabled.
Some UNIX mail servers allow the relaxation of SMTP standards for HELO and VRFY commands. To mimic UNIX behavior, turn this option off. By default, this option is disabled.
The Use Built-In Router option enables routing of mail. If this option is disabled, SLmail will still manage the queues but will not route mail between the queues. For example, SLmail will still accept incoming mail and place it in the In queue. It will also continue to process any mail, which may already be in the Out queue. However, it will not route mail from the In queue to a user's mailbox or from the In queue to the Out queue.
Note: This option is normally used for troubleshooting purposes only.
This option enables the use of the ESMTP protocol. The ESMTP protocol adds some features to the SMTP protocol set. The enabling of this feature is required in order to allow some of the other options and settings work properly. By default, this option is enabled.
If this option is enabled, SLmail will limit the size of inbound and outbound messages. This size limit is entered into the text box to the right of this check box. The size is specified in bytes. If the option is disabled, no size limit is imposed and any value entered into the text box is ignored. By default, this option is enabled.
Note: This option requires that the Use ESMTP Protocol option be enabled.
This option enables the checking of all incoming messages against the ESMTP Size that you have specified. If a message arrives that is larger than the size specified, the message is rejected.
By default, this option is disabled.
This option informs the SLmail router to make sure that the dates passed through the system are in the 4-digit format, as opposed to the 2-digit format. By default, this option is enabled.
This option allows the autoresponder and mailing list portions of SLmail to extract the sender information from the From field of the mail message headers, instead of relying on the SMTP-level definition of the name. By default, this option is enabled.
When a remote computer connects to your computer to deliver mail, it identifies itself by IP address and node name. If the Verify Incoming Hosts option is enabled, SLmail will perform a reverse DNS lookup on the IP address and report the name returned to it in the log file. By default, this option is disabled.
A global size limit can be imposed on all mail boxes on the server. This quota affects all domains and users that do not have disk quotas set explicitly.
You must “turn on” the quotas by selecting the Global Quota Option check box. The Global Quota Status can then be set.
The quota can be set to Enabled and then a Disk Quota size can be specified from 1 to 2147 MB. The Grace Quota is an additional “cushion” that you specify, which the users can use to exceed their mail box Disk Quota temporarily in order to receive a message.
Note: If a mailbox contains more than the sum of the Disk Quota and the Grace Quota, all additional incoming messages will be rejected.
If the quota is set to Unlimited there is not a limit to the size of the mail boxes (until system resources are exhausted).
Note: The Global Quota can be overridden on a Domain or User level for even more control over system resources.
The Quota can be set to Disabled, which will block all incoming mail to the server, even to domains and users that are set to “Unlimited”. (This may be appropriate when you are taking the server down temporarily for maintenance.)
For more information see the section on Mailbox Quotas in this documentation.