This article will show you how to test if your computer can successfully open a connection to your mail server's services. It is a useful exercise, as it can help to determine if your computer has a general problem connecting to your email service, or if the problem lies within your connection settings in Postbox.
Open a CMD (Windows) or Terminal (Mac) window
Windows users should run the built-in CMD.exe program from the Start button. Mac users should start the Terminal app from Applications/Utilities.
Windows Users: It should be noted that the telnet application is not automatically enabled in Windows Vista/7/8, so you will have to enable it first. On Windows Vista/7, this is a case of following this process:
- Click the Start button, and open Control Panel.
- Select Programs and Features.
- Select Turn Windows features on or off.
- Select the Telnet Client option.
- Click OK.
macOS Users: modern versions of macOS do not have telnet installed. To install, open a terminal and paste in this command:
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
To test a POP server (Non SSL method)
Enter the following command, replacing servername either with your domain name or your Home Server name:
telnet servername 110
e.g. if your Home Server is mail.foo.com
telnet mail.foo.com 110
You should get a response that ends with:
+OK Dovecot ready.
If you do not see this after a few seconds, then your computer is unable to connect to your POP3 service.
Just type quit and hit <return> to exit.
To test a POP server (SSL method)
This is only available on the Mac platform (or other Linux based systems).
Enter the following command, replacing servername either with your domain name or your Home Server name:
openssl s_client -connect servername:995 -quiet
You should get a response that ends with:
+OK Dovecot ready.
If you do not see this after a few seconds, then your computer is unable to connect to your POP3 service.
Just type quit and hit <return> to exit.
To test IMAP server (Non SSL method)
Enter the following command, replacing servername either with your domain name or your Home Server name:
telnet servername 143
e.g. if your Home Server is mail.foo.com
telnet mail.foo.com 143
You should get a response that ends with something similar to:
* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
If you do not see this after a few seconds, then your computer is unable to connect to your IMAP service.
To exit, enter this command:
a1 LOGOUT
To test IMAP server (SSL method)
This is only available on the Mac platform (or other Linux based systems)
Enter the following command, replacing servername either with your domain name, or your Home Server name:
openssl s_client -connect servername:993 -quiet
Again, you should get a response that ends with:
* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID
ENABLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
If you do not see this after a few seconds, then your computer is unable to connect to your IMAP service.
To exit, enter this command:
a1 LOGOUT
Logging into an IMAP Server with Your Credentials
In order to access your mailbox you will need 3 things:
- An active internet connection
- The address of your IMAP-capable mail server (e.g. mail.foo.com)
- Your username and password
The first thing to do is to open a connection from your computer to your mail server. Within a command prompt, type in:
telnet mail.foo.com imap
You should receive a reply like:
* OK Courier-IMAP ready. Copyright 1998-2008 Double Precision, Inc.
Then log in:
login me@mydomain.com mypassword
If this doesn't work, try adding the "tag" prefix, like this:
tag login me@mydomain.com mypassword
This should give you:
OK LOGIN Ok.
When you have finished, here's how you quit:
logout (or tag logout)
This should give you:
* BYE Courier-IMAP server shutting down
OK LOGOUT completed