Field

Description

Use DNS lookup

Select this option if your server is going to send messages directly.

When sending a message, IceWarp Server will query DNS servers to locate the receiving server's IP address.

DNS servers can be specified in the Internet Connection node.

Use relay server

Select this option if you wish IceWarp Server to use a relay server to send messages.

This is useful when your domain has no public IP address or you are on a slow dial-up connection via an ISP that allows you to use their email server to send messages.

Connections to your ISP's mail server tend to be faster than other servers on the internet so your messages may be delivered more quickly, keeping your connection costs down.

You should enter the hostname or IP address of the relay server.

If your relay server requires authentication this can be achieved by using one of the following 'full URL' forms of the hostname: <username>:<password>@<MyISPhostname>

or

<username@domain.com>:<password>@<MyISPhostname>

The second option should be used if your username is a full email address.

Example:

john@doe.com:johnspassword@mail.MyISP.com

You can specify multiple relay servers here, separated by semicolons. If IceWarp Server cannot connect to the first relay server, it will try to the second one etc.

NOTE: Relay servers may use different ports for SMTP service then the default one (25).

In this case, you have to specify it: <username>:<password>@<MyISPhostname:port>

or

<username@domain.com>:<password>@<MyISPhostname:port>

Deliver messages via relay server when direct delivery fail

Checking this option only has an effect if you have selected Use DNS lookup and you have defined a relay server (or servers) in the Use relay server text box, IceWarp Server will attempt delivery to via these server(s) if all direct delivery attempts fail.

NOTE: This option overrides the SMTP retry interval settings.

Max message size

Check this box and enter a value to limit the size of messages that can be sent or received via the IceWarp Email Server (in the above screenshot 10MB).

If a user tries to send a message larger than the specified size it will be rejected.

NOTE: This limit will be overridden by any non-zero Domain-specific limits or User-specific limits if Override global limits is checked within Global Settings – Domains.

NOTE: WebClient lets you upload files in a different way. Via SmartAttach or to upload files in groupware objects (such as Files object or files attached to contacts, events etc). In this case, IceWarp Server uses a different limit defined in icewarp/php/php.ini. The default is 2 GB (upload_max_filesize = 2048M). You can change this setting to match your global maximum message size policy.

Delivery reports

Check this box if you want the delivery reports to be available for users.

There are following delivery statuses:

• Delivered – message delivered (only for local recipients).
• Sent – message successfully sent outside/relayed.
• Queue – message was temporally deferred, the server will try to send it later.
• Error – message was bounced back with an error (check your inbox for a detailed error message).

For further information about delivery reports in IceWarp WebClient, refer to IceWarp WebClient User Guide.

Field

Description

Undeliverable after

If IceWarp Server cannot contact a server to deliver a message it will queue the message and retry delivery at regular intervals.

Specify a value and time unit.

Warning after

If IceWarp Server cannot contact a server for the specified number of hours the sender is informed.

This message is only a warning, IceWarp Server will continue trying to deliver the message.

Specify a value and time unit.

Report alias / Report name

The report alias and name are used to generate the From: header in any system generated report messages (for example the undeliverable report, disk space monitor report, etc.).

Bad mail

If the sender of a message cannot be ascertained (e.g. there is no From: header) and an undeliverable message report is generated it will be sent to the recipient(s) listed here.

Multiple addresses can be specified, separated by semicolons.

Return truncated message

Check this option and only message headers are returned if the message cannot be delivered.

Check this option and if the message cannot be delivered, approximately 4 KB of the original message are returned as an attachment. This includes the message headers and – in some cases – also part of the original message body.

Send information to administrator

Check this option and all undeliverable messages will be copied to the administrator.

Bounce back messages

Choose a process option for bounce back messages.

All senders - Process bounce back messages for all senders.

Local senders only - Process only for Local Senders.

Disabled - do not process bounce back messages.

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 spamming - because of this the recommended bounce back level in MDA mode is "local senders".

If you want to prevent delivery of bounce backs, you can create the smtpbouncebackbypass.dat file and place it into the icewarp/config/ folder. Use the same syntax as for e. g. spambypass.dat file (Anti-Spam – General – Other).

Retry Intervals

Press this button to open a dialog allowing you to specify retry intervals (from the previous attempt) for failed deliveries:

Use the Add button to add a new retry time.

Use the Edit and Delete buttons to modify or remove a retry time.

Use the Up and Down arrows to move a retry time in the list.