IMAP, POP3, and SMTP Explained: CURIAWEB E-Mail Server, Ports, and Settings

When setting up a CURIAWEB email address in Outlook, Apple Mail, Thunderbird, on an iPhone, iPad, or Android device, you will encounter terms like IMAP, POP3 and SMTP. These protocols fulfill different tasks in receiving, synchronizing, and sending emails.

For most applications, we recommend at CURIAWEB IMAP for incoming mail and SMTP for outgoing mail. POP3 is also available, but is usually less suitable for using a mailbox on multiple devices.

In this article, you will find the CURIAWEB server data and learn which protocol is used for which purpose.

CURIAWEB Standard: For a normal email account, we recommend IMAP via port 993 and SMTP via port 465. Both connections are used encrypted and require authentication with your full email address and the email account's password.

CURIAWEB email settings at a glance #

Setting	Value
Username	Your complete email address
Password	Email account password
Incoming mail server	mail.your-domain.ch
IMAP port	993
POP3 port	995
Outgoing mail server	mail.your-domain.ch
SMTP port	465
Encryption	SSL/TLS
Authentication	Required for IMAP, POP3 and SMTP

The server name is based on your own domain. Replace your-domain.ch with the actual domain name of your email address.

For the email address:

info@meine-firma.ch

is the mail server, for example:

mail.meine-firma.ch

As a username you use:

info@meine-firma.ch

Important: Always use the full email address as the username. Only Info or another part before the @ is not sufficient for registration.

What is IMAP? #

IMAP stands for Internet Message Access Protocol. It is used by email programs to access messages and mail folders of a mailbox on the mail server.

The decisive advantage is that the mailbox is generally managed on the server. Your email program synchronizes with this message store.

This makes IMAP particularly well-suited when you use the same email address on multiple devices.

You can, for example, access your CURIAWEB mailbox simultaneously with:

• Microsoft Outlook on your computer
• Apple Mail on your Mac
• Mail on your iPhone or iPad
• the Gmail app on an Android device
• Mozilla Thunderbird
• Webmail

use.

When you mark a message as read, move it, or delete it on one device, this change can also be reflected on the other connected devices via IMAP.

CURIAWEB IMAP Settings #

For encrypted IMAP access, you use:

Server: mail.deine-domain.ch
Port: 993
Encryption: SSL/TLS
Authentication: required
Username: full email address
Password: email account password

IMAP over port 993 is our recommended configuration for the inbox.

What does synchronization mean in IMAP? #

IMAP is not just a method for downloading new messages. The email program reflects the server-side state of the mailbox and synchronizes changes.

For example, if you move a message to a folder on your smartphone, this change can then also become visible in Outlook or Webmail.

The same generally applies to the read status or deleting messages.

Important: When you delete an email in a synchronized IMAP folder, you should not assume that it will still remain permanently on another device. The deletion action may also be synchronized with the server.

Does IMAP also save emails on the computer? #

Many email programs store local copies or a cache of synchronized IMAP messages. As a result, content that has already been synchronized can be available, at least in part, even without a permanent internet connection.

However, this does not change the fundamental principle: with IMAP, the server-side mailbox is the central basis for synchronization.

Therefore, a locally cached message should not be confused with an independent backup.

Attention: IMAP is not a backup solution. If a message is deleted on the server and this change is synchronized, it can also disappear from the connected email programs.

What is POP3? #

POP3 stands for Post Office Protocol Version 3. POP3 is also used to retrieve emails from a mail server.

However, the operating principle differs significantly from IMAP. POP3 is traditionally designed to download messages from the server to a single device or email program.

Depending on the configuration, messages may remain on the server after retrieval or be removed from the server later.

POP3 can therefore be useful for certain local workflows. However, for users who want to use the same mailbox on multiple devices, IMAP is usually the better choice.

CURIAWEB POP3 Settings #

If you want to use POP3 intentionally, the following settings apply:

Server: mail.deine-domain.ch
Port: 995
Encryption: SSL/TLS
Authentication: required
Username: full email address
Password: email account password

Encrypted POP3 access is via port 995.

IMAP or POP3 – which is better? #

That depends on the desired working method. For most CURIAWEB customers, we recommend IMAP.

Property	IMAP	POP3
manage message inventory on the server side	Yes	Not in the same synchronization model
Suitable for multiple devices	Very good	Restricted
Synchronize folders	Yes	No, like with IMAP
Synchronize read status	Yes	No, like with IMAP
Local news retrieval	Possible	Central function
CURIAWEB Recommendation	Yes	Only on conscious demand

If you use your email address on a computer and a smartphone, for example, you should choose IMAP.

What is SMTP? #

SMTP stands for Simple Mail Transfer Protocol. While IMAP and POP3 are used to access incoming messages, SMTP is for the Sending emails responsible.

When you in Outlook, Apple Mail, or Thunderbird on Send you click, your email program hands the message over to the configured SMTP server.

The SMTP server then handles the further processing or transmission of the message.

CURIAWEB SMTP settings #

For the normal CURIAWEB configuration, you use:

Server: mail.deine-domain.ch
Port: 465
Encryption: SSL/TLS
Authentication: required
Username: full email address
Password: email account password

For the outbox, we are therefore using the same server name as for IMAP and POP3. However, the protocol and port used are different.

Why does SMTP require authentication? #

A mail server must not allow arbitrary internet users to send messages through it without authentication.

Therefore, your e-mail program must authenticate with the CURIAWEB SMTP server.

For this, you use your full email address and the password of the email account.

Typical error: Emails can be received, but not sent. In this case, the incoming mail server is frequently set up correctly, while the username, password, port, or authentication for the SMTP server are missing or incorrectly configured.

Incoming mail server and outgoing mail server are different functions #

Even though the same hostname is used for both functions in CURIAWEB, they are technically different services.

For the IMAP inbox:

mail.deine-domain.ch:993

For outbound mail via SMTP:

mail.deine-domain.ch:465

The server name is the same, but the protocol and port determine which service is accessed.

What is a port? #

A server can offer different services via the same network address. The port number helps determine which service an application wants to communicate with.

For the CURIAWEB email configuration, these ports are particularly relevant:

Minutes	Port	Task
IMAP	993	Encrypted access to emails and mail folders
POP3	995	Encrypted email retrieval
SMTP	465	Encrypted email transmission

If the correct server name is combined with an incorrect port, the connection can still fail.

What does SSL/TLS mean for email? #

TLS serves to encrypt the connection between your email client and the mail server. In the context of email clients, the term is often still used for this purpose SSL/TLS used.

With the standard CURIAWEB configuration, you use encrypted connections for IMAP, POP3, and SMTP.

This concerns the connection between your device and the mail server. However, the transport encryption of this connection is not the same as end-to-end encryption of the actual message content.

Briefly explained: SSL/TLS protects the connection to your mail server. It does not automatically mean that an email is exclusively end-to-end encrypted along its entire path to the recipient.

Why is the username the full email address? #

Numerous domains and email accounts can be managed on a mail server.

A username like:

Info

would therefore not be clear enough.

The complete email address:

info@meine-firma.ch

identifies the specific mailbox instead.

Therefore, always use the full email address as the username for IMAP, POP3, and SMTP.

Which password must be used? #

For the registration, you use the password of the respective Email accounts.

This password is not automatically identical to your password for the CURIAWEB customer center or cPanel.

If you use multiple email addresses, each email account can have its own password.

What does mean mail.your-domain.ch? #

mail.your-domain.ch there is a scheme for the mail server of your own domain in our instructions.

You must your-domain.ch replace with your actual domain.

Examples:

Email address	Mail server
info@meine-firma.ch	mail.meine-firma.ch
kontakt@beispiel.ch	mail.beispiel.ch
office@firma-example.com	mail.firma-example.com

Attention: Do not translate literally mail.your-domain.ch into your email program. Use the mail server of your actual domain.

Where can I find my email account settings? #

You can also view the settings available for your hosting account in cPanel under your email account.

To do this, open the section in cPanel Email -> Email accounts and the corresponding function for connecting or setting up a device for the desired account.

We explain how to create a new mailbox at Create an email account in cPanel.

Why can receiving work even though sending does not work? #

Because inbound and outbound mail use different protocols.

If IMAP is correctly configured, you can receive and synchronize messages. At the same time, an incorrect SMTP configuration can prevent you from sending messages.

Therefore, a working inbox does not prove that the outbox is also configured correctly.

In case of shipping issues, you should specifically check the server name and SMTP port 465, Check SSL/TLS, username, password, and SMTP authentication.

Why can sending work even though no emails are received? #

The reverse case is also possible.

When SMTP is working correctly, your email program can send messages. A faulty IMAP configuration can still prevent new messages from syncing.

Then check in particular:

IMAP Server: mail.deine-domain.ch
Port: 993
SSL/TLS
Username: full email address
Password: email account password

Webmail requires no setup in the email program #

Webmail allows you to access your mailbox via a web browser.

You don't need to configure IMAP or SMTP for this in Outlook, Apple Mail, or Thunderbird.

Webmail is therefore also a helpful sanity check for problems with a locally configured email program.

If you can log in to webmail and send and receive messages there, the email account and server-side login are fundamentally working.

We explain how to access it at Use Webmail.

IMAP does not sync calendars and contacts #

IMAP is responsible for emails and mail folders.

Therefore, setting up an IMAP account in Outlook, Apple Mail, or Thunderbird does not automatically mean that calendars and contacts will also be synchronized via IMAP.

Calendar and contact synchronization use different technical processes or services respectively.

IMAP is not the same as Exchange #

A standard CURIAWEB email address is set up as an IMAP account in an email program.

This does not turn the mailbox into a Microsoft Exchange or Microsoft 365 account.

IMAP provides synchronization for emails and mail folders. Exchange-based accounts can also provide additional features such as integrated calendars, contacts, or enterprise features.

What do SPF, DKIM, and DMARC have to do with IMAP and SMTP? #

IMAP, POP3, and SMTP describe mailbox access and message transmission. SPF, DKIM, and DMARC on the other hand, fulfill tasks in the authentication and evaluation of emails between domains and mail servers.

These technologies should therefore not be confused with each other.

For example, you can use the correct IMAP and SMTP settings in Outlook and still have a separate issue with your domain's SPF, DKIM, or DMARC.

We explain how these three procedures work together under SPF, DKIM, and DMARC explained with CURIAWEB Hosting.

SpamExperts Incoming Filtering does not change your IMAP settings #

If SpamExperts Incoming Filtering is used for your domain, this affects the delivery of incoming messages to your domain.

SpamExperts receives the message via the corresponding MX servers, filters it, and then forwards it to the destination mail server.

Your email program will continue to access your mailbox via IMAP afterwards.

That is why you do not enter a SpamExperts MX server as an IMAP or POP3 server in Outlook, Apple Mail, or Thunderbird.

Briefly explained: MX determines where emails for your domain are delivered. IMAP and POP3 determine how you subsequently access your mailbox.

SpamExperts Outgoing Filtering can change the SMTP server #

With SpamExperts Outgoing Filtering, the situation is different because this service affects outgoing email traffic.

If SpamExperts Outgoing Filtering has been explicitly set up for your account or your mailing configuration, different SMTP data may apply compared to the standard CURIAWEB configuration.

In this case, you use the SMTP settings intended for SpamExperts Outgoing Filtering.

You can find more information at Set up SpamExperts Outgoing Filtering.

MX servers are not IMAP or SMTP settings #

A common misconception is to use a domain's MX records as server data for the email client.

MX records are stored in a domain's DNS and determine which mail servers should receive emails for that domain.

They are not automatically the servers your Outlook, smartphone, or Thunderbird should connect to.

For the standard CURIAWEB configuration, you continue to use in your email program:

IMAP: mail.deine-domain.ch / Port 993
SMTP: mail.deine-domain.ch / Port 465

What should you do in the event of a certificate warning? #

If your e-mail program shows a certificate warning when establishing a connection, you should not simply ignore it.

Check the entered mail server first.

In the normal CURIAWEB configuration, it follows this schema:

mail.your-domain.ch

A certificate warning can occur, among other things, when the hostname used does not match the server's certificate.

Safety Notice: Do not simply add a permanent exception for a certificate warning. Check the server name and connection settings first.

What happens after a password change? #

If you change the password of an email account, devices that are already set up may still use the old saved password.

This can suddenly cause login errors, even though the server name and ports remain correctly unchanged.

Therefore, update the password on all devices and in all email programs that use the affected mailbox.

Consider both the inbox and SMTP authentication for sending.

Which protocol should you use? #

For a normal CURIAWEB email address, the decision is easy in most cases:

Incoming mail:
IMAP
Port 993
SSL/TLS

Outgoing mail:
SMTP
Port 465
SSL/TLS

Username:
full email address

Authentication:
required

POP3 over port 995 is available as an alternative for special requirements. If you do not have a specific reason for POP3, we recommend IMAP.

Summary #

IMAP, POP3, and SMTP fulfill different tasks.

IMAP synchronizes your mailbox and mail folders with the server. Therefore, we recommend IMAP for most CURIAWEB email accounts and especially when using multiple devices.

POP3 is also used to retrieve messages, but does not work on the same synchronization principle as IMAP.

SMTP is responsible for sending emails and is required regardless of whether you use IMAP or POP3 for your inbox.

For the normal CURIAWEB configuration, the following apply:

IMAP:
mail.your-domain.ch
Port 993
SSL/TLS

POP3:
mail.your-domain.ch
Port 995
SSL/TLS

SMTP:
mail.your-domain.ch
Port 465
SSL/TLS

Username:
full email address

Password:
email account password

Authentication:
required

Therefore, for most users our recommendation is: IMAP 993 for incoming mail and SMTP 465 for outgoing mail – both encrypted and with authentication.