In an effort to help keep your server secure, Telnet is being removed from the latest version of Ubuntu (Bionic) . If you require telnet, DreamHost recommends running it on your local computer instead.
Telnet is a deprecated protocol used to remotely log in to another computer or communication equipment over a network. The Telnet protocol offers no security. Using Telnet sends all communications, including passwords, over the wire in plain text. For this reason, it is only recommended that SSH be used instead for running any command with secure data. Telnet should only be used for very basic testing purposes.
As stated above, Telnet should never be used with any passwords or sensitive data as it is not secure. However, you can use Telnet to run some basics tests on your DreamHost services.
Testing a connection to a mail server
If you find your mail client is not connecting as it should, you can test the connection between your local computer and the mail server.
View the following article for instructions on how to locate your correct mail servername.
- Run the following command via SSH or in the Windows command prompt to test your connection:
[server]$ telnet imap.dreamhost.com 143
If connecting properly, it responds with something like this:
Trying 18.104.22.168... Connected to imap.dreamhost.com. Escape character is '^]'. * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
- To exit the telnet session, type CTRL + ] on your keyboard. This changes the command prompt to show as 'telnet>'.
Back in the terminal, type in the word 'close' to close the session.
Telnet can be run on your Windows computer also (assuming you have enabled it). View the following articles for details.