Collax Mail Server. Howto. This howto describes the setup of a Collax server as mail server.

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Collax Mail Server

This howto describes the setup of a Collax server as mail server.


Collax Business Server Collax Groupware Suite

Collax Platform Server including Collax Communication module


A Collax server is to be set up as a mail server in an existing infrastructure. The users are to retrieve their mail from the Collax server and manage their mail. This howto describes the setup from scratch without using wizards.


The first step is the creation of a mail domain. In this way, the server knows that it is now responsible for one or several defined mail domains (and what to do with e-mail for a particular domain). This dialog is located under "Services Mail and Messaging Mail Transport Domains".

Locally Administered

If the Collax server itself is to serve as the mail server on which the e-mail from one or several mail domains is to be managed, select the item "Locally administered" under "Type".


Internal Relay

If the Collax server is to forward e-mail to an internal mail server (e.g. Collax Groupware Suite), select the option "Internal relay".

Filter e-mail Enable this option to pass all e-mail to recipients in this domain through the spam and virus filters. This does not affect the header and MIME filters.

Masquerade subdomains If you enable this option, mail to subdomains of the configured domain will be treated like e-mail to the actual domain.

Login If the mail server specified above requests authentication, enter the login here.

SMTP Outbound

Here you can configure the transmission of mail. Due to the large amount of spam, many providers no longer accept any e-mail from dynamic IP addresses. In this case, it is necessary to use an e-e-mail relay. Ask your e-mail provider for the relay details. If the MX record for your mail domain is set up for your company's external IP, you do not need a mail relay. In this case, directly transmitted e-mail will also be accepted by other mail servers.


Use TLS Here you can determine whether and when TLS is to be used for outgoing e-mail. TLS serves the encryption of the SMTP session and thus also the encryption of the authentication information.

Rewrite sender domain to mail domain If this option is activated, the sender address of e-mails of users who use the mailbox name as sender address will be rewritten so as to correspond to one of the "official" e-mail addresses.

Alternative SMTP server name An SMTP server name is required for the communication via SMTP. If the SMTP server name is to be different from the internal host name, a server name that can be resolved by external DNS servers is to be entered here for the MX record. If this field is left blank, the entered FQDN of this server will be used as SMTP server name.

SMTP Reception

Here you can configure the settings for incoming connections. This includes mail from external employees that send e-mail from their home offices and internal employees or e-e-mail delivered via MX record.

This dialog is located under "Services Mail and Messaging Mail Transport SMTP reception".

Tick "Enable SMTP-AUTH" if external employees are to send e-mail via the Collax server. For mail to be sent via the Collax server, the e-mail program must first authenticate with the Collax server by means of a login and password. Of course, authentication can also be implemented for internal employees.

Activate "Validate user address" only if external mail servers do not use authentication for the delivery. This option checks whether the login is linked to the sender address. If this is not the case, the e-mail will be rejected.


"Allow mail relay" authorizes the sender to send e-mail via the Collax server without authentication. Only groups that are truly entitled to use the Collax server as mail relay should be authorized. The system automatically prevents the setup of an open relay that could be misused by spammers. From the Internet, transmission is only possible with authentication. For this, "Enable SMTP-AUTH" must be activated as described above.

Under the "Options" tab, you can configure further settings like "Global mail filter", "Auto alias", etc. If you already want to filter out spam e-mail in the SMTP dialog, this can be configured here. Attention: Do not use these spam protection options if e-mail is not delivered directly, but retrieved from another mail server. Upon retrieval, the e-mail can no longer be rejected.


Under "IMAP and POP3", you can configure the options for retrieving e-mail from the Collax server. This dialog is located under "Services Mail and Messaging Mail Storage IMAP and POP3".


Under the "Permissions" tab, you can select the groups to be granted access to Web mail, POP3, and IMAP. The selected groups must contain both the users and the networks that are to be granted access. For internal staff, for example, the local network must be a member of the group.

Shared Folders


Members of the "Users" group may subscribe to the shared "Teamfolder" and store e-mail in this folder with drag and drop. The "Administrators" group is also permitted to delete e-mail. In the e-mail program, the subscribed "shared folders" appear as subfolders of "public".

Administrative IMAP Folders


Mailing Lists

Mailing lists can be used to deliver e-mail to a specific address to multiple users. Thus, e-mail can be sent to an entire department using only one address. Mailing lists can be defined under "Services Mail and Messaging Mail Transport Mailing Lists".

All users of the "Sales" group receive e-mail sent to the mailing list

Furthermore, the mailing list is assigned the alias Additionally, the e-mail address is to be included in the mailing list.

External Mailboxes and Retrieval Times


There are different e-mail account types. POP3 and IMAP are the most common types. Every user has a separate mailbox with the provider. A separate retrieval must be configured for each user.

Do not verify sender mail domain Normally, e-mail is checked to make sure whether the mail domain of the sender exists in the DNS database. E-mail from non-existing senders is discarded. Enable this option to disable the verification.

Do not delete e-mail from server If you enable this option, the retrieval job will not delete downloaded e-mail from the server. This is useful for test purposes or if several systems access the same mailbox. However, the mailbox should regularly be emptied in some other way.

Note: In some cases, enabling this option can result in repeated delivery of the same e-mail.

Fetch all e-mails If this option is set, all messages existing on the e-mail server will be fetched during each fetch process, even if the seen flag has already been set for messages. This option cannot be combined with the option "Do not delete e-mail from server".

No rewriting Normally, the addressing headers of an e-mail message are rewritten when mail is fetched via POP3 or IMAP. This affects addresses in the To, From, CC, BCC, and Reply-To fields.

Use this option to prevent the mail system from editing the headers. Depending on the provider or mailbox protocol, you may need to enable this option, as otherwise the spam or header filters cannot filter the e-mail. If you retrieve mail from a POP3 multidrop mailbox, the From address may always contain "". The delivery of the e-mail may work, but the spam or header filtering may not. If this is the case, enable this option to make the filter mechanisms work.


Retrieval Times




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