Advanced

The Advanced tab allows you set advanced mail service settings.

Figure. General view: Advanced tab.

IMAP Section

Field	Description
Enable full text search	Check the box if you want to enable the full text search function in IceWarp WebClient.

MDA Queue section

Field	Description
Processing incoming messages in MDA queue	Check this option to have the MDA queue used. You should only consider using this option on high-traffic servers or servers that have major Antispam and/or IceWarp Antivirus processing. Note: Huge MDA queues (e.g.: more than 13 000 emails) can cause SMTP not working properly. If messages are not flowing, you can either increase number of threads or run smtp.exe/systray using Command Line. In this case, it is not started as a service but as an application. As a service, it has timeout set to 30 second and when there is a huge MDA queue it simply does not make it to start in the timely fashion. As an application, it does not have any timeout set.
Use MDA queue for internal message delivery	Check this option to have all internal messages processed via the MDA queues. This means that any internal message (bounce back, server generated message, Account Forwarder message, etc.) will be processed via an MDA queue and all filter, rule, Antispam, IceWarp Antivirus, etc. processing will be performed on the message.
Maximum number of simultaneous threads	Specify the maximum number of threads to use for processing of incoming messages. This can help alleviate problems on high-load servers where the sending server times out, but IceWarp Server still processes and delivers the message. The sending server then tries again, and a duplicate message is received. If you enter a non-zero value here then any incoming messages are stored immediately to an incoming folder, for later processing, and the session is closed so there are no timeouts. Recommended value for non-high-load servers is 8. Increase the value if not sufficient due to the server load. Note: In MDA mode, a message is accepted and then processed by other filters at a later time. If a message is then refused, a bounce back is sent to the sender. If the sender's address is spoofed than an innocent recipient could get the bounce back which would be considered as spam – because of this the recommended bounce back level in MDA mode is Local senders only. (Mail Service > General > Delivery (on page 1) > Bounce back messages.)

Field

Description

Processing incoming messages in MDA queue

Check this option to have the MDA queue used.
You should only consider using this option on high-traffic servers or servers that have major Antispam and/or IceWarp Antivirus processing.

Note: Huge MDA queues (e.g.: more than 13 000 emails) can cause SMTP not working properly. If messages are not flowing, you can either increase number of threads or run smtp.exe/systray using Command Line. In this case, it is not started as a service but as an application. As a service, it has timeout set to 30 second and when there is a huge MDA queue it simply does not make it to start in the timely fashion. As an application, it does not have any timeout set.

Use MDA queue for internal message delivery

Check this option to have all internal messages processed via the MDA queues.
This means that any internal message (bounce back, server generated message, Account Forwarder message, etc.) will be processed via an MDA queue and all filter, rule, Antispam, IceWarp Antivirus, etc. processing will be performed on the message.

Maximum number of simultaneous threads

Specify the maximum number of threads to use for processing of incoming messages. This can help alleviate problems on high-load servers where the sending server times out, but IceWarp Server still processes and delivers the message. The sending server then tries again, and a duplicate message is received.

If you enter a non-zero value here then any incoming messages are stored immediately to an incoming folder, for later processing, and the session is closed so there are no timeouts.
Recommended value for non-high-load servers is 8. Increase the value if not sufficient due to the server load.

Note: In MDA mode, a message is accepted and then processed by other filters at a later time. If a message is then refused, a bounce back is sent to the sender. If the sender's address is spoofed than an innocent recipient could get the bounce back which would be considered as spam – because of this the recommended bounce back level in MDA mode is Local senders only. (Mail Service > General > Delivery (on page 1) > Bounce back messages.)

Forwarding of local messages to local recipients is not logged unless local MDA is enabled.
When MDA is set, the <install_dir>/mail/_incoming folder is used instead of the one defined under System > Storage > Directories.
Local MDA changes these folders only for local emails. Auto-responder will always back-scatted regardless MDA is set or not.
For detailed information, refer here: http://www.spamcop.net/fom-serve/cache/329.html.

SMTP section

Field	Description
Maximum SMTP hop count	Sometime a message can get into a 'relay loop', where it is being passed between servers trying to find a delivery point. A hop is defined as one pass of the message to a server. Specifying a value here instructs IceWarp Server to count the number of servers the message has been through, compare it with this value, and reject the message if the number of hops exceeds the specified value.
Maximum SMTP server recipients	Specify the maximum number of server session recipients allowed in an outgoing message. (I. e. number of recipient addresses in one message.) This can be used to protect your server from overload.
Maximum SMTP client recipients	Specify the maximum number of client session recipients allowed in an outgoing message. Some systems do not like receiving many emails in one session, this option can split outgoing client sessions based on the number of recipients If the number is exceeded the message will be split into multiple sessions.
Exceptions	Here you can override Maximum SMTP client recipients for specific target domains. Click the button to open a dialog allowing you enter the target domain and the override value.
Maximum number of messages sent to one domain per minute	Messages going to a remote domain are aggregated and sent together. Enable this option to throttle the sending speed by specifying the maximum number of outgoing messages per minute to the same remote domain. Emails violating the limit will be held in the retry queue for as long as necessary. Leave this option disabled for fastest message delivery. First, check the box, if you want to enable this feature. Next, in the edit field, specify the maximum number of outgoing messages per minute. This global limit will be applied to all the outgoing messages, except for those specified in the Exceptions list. A value of 0 indicates no limit. If needed, specific domains can be given a value different from the global limit. For this, open the Exceptions dialog, add your domains and indicate the number of outgoing sessions per minute per domain.
Exceptions	Click the button to open the Maximum number... dialog. Click the Add button to specify a domain name and value to override the value in the edit field. It is even possible to specify one limit to a set of domains (delimited by semicolons). In this case, this group of domains has common limit.
Maximum number of messages sent from one domain per minute	Check the box, if you want to enable this feature. Specify the maximum number of outgoing messages into the edit field. Enable this option to throttle the sending speed and specify the maximum number of outgoing messages from the same domain per minute. Emails violating the limit will be held in the retry queue for as long as necessary. Leave this option disabled for fastest message delivery. Internally some messages can have higher sending priority and skip ahead of others, but there is no way to influence it. See Mail Service > General > Spool Management for details. To limit number of Incoming connections in specific domain leave the value to 0, open the Exceptions dialog and add your domain and limit the number of client sessions per minute.
Exceptions	Click the button to open the Maximum number... dialog. Click the Add button to specify a domain name and value to override the value in the edit field. It is even possible to specify one limit to a set of domains (delimited by semicolons). In this case, this group of domains has common limit.
Enforce TLS/SSL on secondary SMTP port	Check the box if you want to enforce the secondary SMTP port (587) to communicate using this protocol(s). Warning: When the following commands are turned on: c_mail_smtp_delivery_messagesubmission c_mail_smtp_delivery_enforcetlsonsecondarysmtpport, this combination of settings can cause fails to send out email by PHP mailer because of not STARTTLS command is supported.
Use TLS/SSL	Check this box and IceWarp Server will connect to remote servers using TLS/SSL, if the remote server is capable of this. NOTE: If you want to use TLS instead of SSL while sending/receiving mails, use the basic ports in email client (25 for SMTP) and mark to use TLS. (For SSL, use the usual SSL ports).
Hide IP address from Received: header for all messages	Checking this option tells IceWarp Server not to put the IP address in a messages Received: header. This effectively stops people from being able to work out your local network configuration.
Add rDNS result to Received: header for all messages	Check this option and a reverse DNS lookup will be performed for each incoming message and the result added to the message headers. Warning: Using this option improves security but can severely impact performance on high-load Servers.
Add Return-Path header to all messages	Check this option and IceWarp Server will add a Return-Path header to the email. This can be useful for debugging and checking where an email came from.
Dedupe email messages	If a user has multiple aliases and a message is sent to more than one of the aliases the end User will receive multiple copies. Also, if a user is a member of more mailing lists (or groups) and these lists (groups respectively) receive the same message, this user will receive multiple copies. Check this option and IceWarp Server will check for duplicate message to the same end user and only deliver one of them. Note: If the Bounce back for failed recipients feature in WebClient (Tools > Administrator Options > Mail > General) is enabled, this option can not be used. As a result of enabling of both options, users would receive duplicated messages. Warning: The following scenario can cause a loss of messages that could be completely deleted : standard domainstatic route --> forward to a host (relay server) catch-all forward to this static route (2) Do NOT use the Dedupe email messages option in this case!

For general information on Spool Manager, refer to the Reference > General page.

Header/Footer section

IceWarp Server can automatically insert a header and/or footer to messages using this option.

This will affect all domains within your server. If you want to specify different headers and footers for different domains you should use the domain-based Header/Footer button in Domain > Options – but you must enable the facility in this panel.

Field	Description
Active	Check the box to enable header/footer processing.
Header/Footer	Click the button to define header/footer files. The Header/Footer dialog opens.

Figure. Advanced tab: Header/Footer dialog.

Field	Description
Header text file	A fully qualified path to a text file which will be inserted as a header to text format messages.
Header HTML file	A fully qualified path to an HTML file which will be inserted as a header to HTML format messages. Note: The extension of this file must be htm or html for this function to work correctly.
Footer text file	A fully qualified path to a text file which will be inserted as a footer to text format messages.
Footer HTML file	A fully qualified path to an HTML file which will be inserted as a footer to HTML format messages. Note: The extension of this file must be htm or html for this function to work correctly.
Top reply text file	A fully qualified path to a text file which will be defined at the end of the top reply within an email.
Top reply HTML file	A fully qualified path to an HTML file which will be defined at the end of the top reply within an email. Note: The extension of this file must be htm or html for this function to work correctly.
Configure Top Reply Delimiters	Click this button to configure top reply delimiters. This file contains additional patterns used to detect end of top reply in email message.
Local to local	Header and footer will be inserted into a message if both the sender and recipient are local.
Remote to local	Header and footer will be inserted into a message if the sender is remote and recipient is local.
Local to remote	Header and footer will be inserted into a message if the sender is local and recipient is remote.
Remote to remote	Header and footer will be inserted into a message if both the sender and recipient are remote.

If you are using HTML headers or footers you should only use HTML found within the <BODY> tag. It is recommended to specify both HTML and plain text files as IceWarp Server will add the appropriate header/footer according to message format. You can use vCard variables for header/footer. All variables are available in example directory - variables.dat.html