Set up SpamExperts Outgoing Filtering

With SpamExperts Outgoing Filtering outgoing email traffic is routed through the SpamExperts infrastructure and filtered there. This makes it possible, for example, to detect and control compromised email accounts, abused access credentials, or unwanted mass mailing.

In this guide, we will show you how to create a user for outgoing filtering in SpamExperts and then configure the outgoing SMTP server in your email program.

Briefly explained: Outgoing Filtering affects Shipping of emails. It is not the same as filtering incoming messages for spam and malware.

What do you need for the setup? #

Before you begin, you need access to the SpamExperts Control Panel as well as the login credentials of the email account or the application whose outgoing messages are to be sent via SpamExperts.

For SMTP authentication, you then create a dedicated one in SpamExperts Authenticating User a.

1. Open SpamExperts Control Panel #

Log in to the CURIAWEB customer center and open the corresponding SpamExperts service.

About Manage services you reach the SpamExperts Control Panel.

Switch to the section there Outgoing and open:

Manage users

Create user for outgoing email transmission #

Scroll within Manage users to the area Add a user.

Select the tab there:

Authenticating User

This user will later be used for authentication on the SpamExperts SMTP server.

3. Set username and password #

Enter the desired username or intended email prefix and a secure password.

Then click on:

Add

Important: Safely store the password assigned to the authenticating user. You will need these credentials afterwards for the SMTP configuration of the email program or the sending application.

4. Configure outgoing SMTP server #

Now open the settings of your e-mail program or the application you want to use to send e-mails.

For the outgoing mail server, you use the credentials of the previously created SpamExperts user.

Setting	Value
SMTP server	smtp.antispamcloud.com
Username	full username or email address of the created authenticating user
Password	the password assigned when the user was created
SMTP port	587
Connection security	STARTTLS
Authentication	required

Attention: For SMTP authentication, use the credentials of the authenticating user created in SpamExperts. These credentials may differ from your normal email mailbox credentials.

5. Enable SMTP authentication #

Make sure that authentication is used for the outgoing mail server in your email program.

Depending on the email program, the corresponding setting can be, for example:

• SMTP authentication
• Authentication required
• Outgoing mail server requires authentication

be designated.

Use the credentials of the authenticating user previously created in SpamExperts as the username and password.

6. Use STARTTLS and port 587 #

For the connection to the outgoing SpamExperts server, use:

SMTP Server: smtp.antispamcloud.com
Port:        587
Security:    STARTTLS

With STARTTLS, a connection to the SMTP server is first established and an encrypted TLS connection is subsequently set up.

Make sure your email program actually STARTTLS is used and does not select another encryption method solely based on the port number.

7. Send test email #

After setup, you should verify shipping with a normal test message.

For example, send a message to an external email address that you have access to.

Then check:

• whether the message is sent without an SMTP error message
• whether it reaches the recipient
• whether an error message or non-delivery notification is returned

If the shipping works, the basic SMTP configuration is complete.

If the SMTP login does not work #

If the connection to the SMTP server is established but the login is rejected, check your username and password first.

Pay particular attention to the access data of the one created in SpamExperts Authenticating Users use.

Check also:

SMTP Server: smtp.antispamcloud.com
Port: 587
Security: STARTTLS
SMTP Authentication: enabled

Even an incorrect username, an incorrectly saved password, or an unsuitable connection setting can prevent the SMTP login.

If connection to the SMTP server cannot be established #

Can the email program not connect at all to smtp.antispamcloud.com fixing it, the problem differs from a failed authentication.

In this case, check first:

• whether the SMTP hostname was entered correctly
• port 587 is used
• whether STARTTLS is enabled
• whether the internet connection works
• whether a local firewall or security software is blocking the connection

Note the exact error message of the email program. It helps to distinguish between a connection, TLS, and authentication issue.

When emails are sent but do not arrive #

A successful SMTP login and the successful sending of a message do not automatically mean that the receiving mail server will also deliver the message.

For delivery problems, you should therefore distinguish between different phases:

SMTP connection
↓
Authentication
↓
Message is accepted
↓
SpamExperts processes the delivery
↓
Receiving mail server
↓
Recipient's mailbox

When a message is rejected, you should keep the full error message or non-delivery report. It often contains the crucial clue to the cause.

Outgoing Filtering for applications and websites #

SMTP access can generally also be used for applications that support sending via an authenticated SMTP server.

To do this, the SMTP settings of the respective application must be configured accordingly.

Do not share login credentials unnecessarily across different systems. Separate credentials make management and subsequent troubleshooting easier, provided your specific setup allows for this.

Protect an outgoing user's password #

The SMTP credentials enable the authenticated sending of emails and should therefore be protected like other credentials.

Avoid in particular:

• Sharing the password with an unnecessarily large number of people
• Storage in publicly accessible files
• Use of a weak password
• Publication in screenshots or support forums

If you suspect that the credentials have been compromised, you should change the password in question.

Why Outgoing Filtering is useful #

Outbound spam doesn't just result from intentional mass mailing. Compromised email credentials, infected devices, or abused websites can also send unwanted messages.

Outgoing Filtering therefore creates an additional layer of control for outgoing email traffic.

However, it does not replace the security of the actual email accounts, websites, and end devices. If access is misused, the cause of the compromise must also be investigated and resolved.

When should you contact CURIAWEB support? #

If sending via SpamExperts does not work despite correct settings, record the complete error message if possible.

Particularly helpful are:

• affected domain
• used SMTP server
• used SMTP port
• set encryption method
• exact time of the delivery attempt
• complete error message of the email program

Important: Never send your SMTP password to support via screenshot or unsecured message.

Summary #

For SpamExperts Outgoing Filtering, you first create under Outgoing → Manage users one Authenticating User a.

Then you configure the outgoing mail server of your application with smtp.antispamcloud.com, Port 587, STARTTLS and this user's credentials.

Then carry out a test transmission. In case of problems, you should distinguish whether the connection already fails, the SMTP authentication is rejected, or the message is sent but not delivered later.