Testing your email with Telnet

These FAQs will teach you how to test your IMAP, POP3 and SMTP settings using Telnet

Simply click on a title below to skip to the most appropriate FAQ. You can also click the Top button to return and make another selection.

  1. How can I use Telnet to test my IMAP e-mail account is working?
  2. How can I use Telnet to test my POP3 e-mail account is working?
  3. How can I use Telnet to test that my email account can send mail via SMTP?

How can I use Telnet to test my IMAP e-mail account is working?

This article explains how to use the telnet command in your command prompt console to establish whether your e-mail account is accepting connections.

In circumstances where your usual e-mail client software is not connecting to your IMAP mailbox, using telnet helps you to perform a basic assessment of whether your mailbox is functional. This can help you to eliminate your local software as an issue in being unable to receive your mail.

Please be aware that for Windows Vista & Windows 7, the telnet function is by default disabled and therefore it must be turned on from the Windows Features menu within the control panel.

  • Step 1 of 2Open up your command console – in most versions of Windows, click Start, then Run, type cmd and hit Enter.
  • Step 2 of 2Enter only the text in bold as shown in the example command box below, hitting Enter at the end of each line.
telnet imap.123-reg.co.uk 143
* OK [CAPABILITY IMAP4rev1 SASL-IR SORT THREAD=REFERENCES MULTIAPPEND UNSELECT
LITERAL+ IDLE CHILDREN NAMESPACE LOGIN-REFERRALS UIDPLUS LIST-EXTENDED I18NLEVEL=
1 AUTH=PLAIN] ATLAS/WebFusion Mail Server
01 LOGIN username@domain.com password
01 OK [CAPABILITY IMAP4rev1 SASL-IR SORT THREAD=REFERENCES MULTIAPPEND UNSELECT
LITERAL+ IDLE CHILDREN NAMESPACE LOGIN-REFERRALS UIDPLUS LIST-EXTENDED I18NLEVEL
=1 AUTH=PLAIN] Logged in.

This test will indicate whether or not you are able to connect successfully to your e-mail account. If you are able to connect successfully using Telnet, but not through your regular e-mail client, this suggests the issue may be caused by your local software and you should re-check account settings in your e-mail client in accordance with the vendors help documentation and our e-mail support pages.

If you would like to view all folders within a mailbox you can use the below command when connected via Telnet to the IMAP server.

. list "" "*"

Please note: In the code example above, generic values have been used for the mailbox usernames and passwords.

When testing your e-mail account connection using telnet, please ensure you have the correct e-mail account username and e-mail account password to hand.

How can I use Telnet to test my POP3 e-mail account is working?

This article explains how to use the telnet command in your command prompt console to establish whether your e-mail account is accepting connections.

In circumstances where your usual e-mail client software is not connecting to your POP3 mailbox, using telnet helps you to perform a basic assessment of whether your mailbox is functional. This can help you to eliminate your local software as an issue in being unable to receive your mail.

Please be aware that for Windows Vista & Windows 7, the telnet function is by default disabled and therefore it must be turned on from the Windows Features menu within the control panel.

  • Step 1 of 2Open up your command console – in most versions of Windows, click Start, then Run, type cmd and hit Enter.
  • Step 2 of 2Enter the text as shown in the example command box below, hitting Enter at the end of each line. For each successful command you issue, the server will return the message ‘+OK‘ indicating you should proceed to the next command.
telnet pop.123-reg.co.uk 110
+OK Hello there.
user your-emailmailboxusername
+OK Password required.
pass youremailpassword
+OK logged in.

This test will indicate whether or not you are able to connect successfully to your e-mail account. If you are able to connect successfully using telnet, but not through your regular e-mail client, this suggests the issue may be caused by your local software and you should re-check account settings in your e-mail client in accordance with the vendors help documentation and our e-mail support pages.

Please note: In the code example above, generic values have been used for the mailbox usernames and passwords.

When testing your e-mail account connection using telnet, please ensure you have the correct e-mail account username and e-mail account password to hand.

How can I use Telnet to test that my email account can send mail via SMTP?

This article explains how to use the telnet command in your command prompt console to establish whether your e-mail account can send emails via the the 123 Reg SMTP server.

In circumstances where your usual e-mail client software is not connecting to the 123 Reg SMTP server to send emails, using telnet helps you to perform a basic assessment of whether your email account is functional. This can help you to eliminate your local software as an issue in being unable to send your mail.

Please be aware that for Windows Vista & Windows 7, the telnet function is by default disabled and therefore it must be turned on from the Windows Features menu within the control panel.

  • Step 1 of 2Open up your command console – in most versions of Windows, click Start, then Run, type cmd and hit Enter.
  • Step 2 of 2Enter the text as shown in Bold in the example command box below, hitting Enter at the end of each line. For each successful command you issue, the server a return the message.
telnet smtp.123-reg.co.uk 25
220 mail6.atlas.pipex.net ESMTP Exim 4.71 - "ATLAS SMTP Service" Wed, 13 Jul 201
1 10:47:06 +0100
EHLO smtp.123-reg.co.uk
250-mail6.atlas.pipex.net Hello hns01-fw.internal.gxn.net [195.224.160.13]
250-SIZE 31457280
250-PIPELINING
250-AUTH PLAIN LOGIN
250 HELP
AUTH LOGIN
334 DXNl4gddhbWU3
cwtui3lAcmlja2ljaeFoYewuY2 (Base 64 encoded username)
334 UGFzc3dvcmQ6
YeGjc3ducmE (Base 64 encoded password)
235 Authentication succeeded
MAIL FROM: emailaddress@domain.com
250 OK
RCPT TO: recipent@theirdomain.com
250 Accepted
DATA
354 Enter message, ending with "." on a line by itself
Subject Test using Telnet
.
250 OK id=4Qgw3m-023484q-I5

This test will indicate whether or not you are able to connect successfully to send email from your e-mail account and if you see the statement OK it means the that the email message was sent to the recipient.



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