How to Send Email Using Telnet

PDF download Download Article
Learn how to connect to Telnet & send your message
PDF download Download Article

Software like Thunderbird and Outlook make sending e-mail seem like magic. Well, until your e-mail never arrives at its destination. How can you find out what really happens when you click “Send?” One option is to send a test message from your e-mail provider's outbound server with telnet, a tiny application that came with your computer. You may catch an error message that your e-mail software didn't.

Sending Emails Using Telnet

Open your computer’s terminal window and type “telnet [yourmail.server.com] 25”. Then, type in “HELO [yourdomain].com”. Enter “mail from: [youremail@server].com” and then “rcpt to: [yourfriendsemail@friendsdomain].com”. Then, type “data” and compose your message.

Part 1
Part 1 of 2:

Connecting to the Mail Server with Telnet

PDF download Download Article
  1. If you’re using MacOS or Windows XP, your version of telnet is ready to use. If you have Windows Vista, 2008 server, 7, 8.1 or 10, you’ll need to enable telnet before you can use it. [1]
    • Windows Vista, 2008 server, 7 and 8.1: Click on the Start Menu and then select Control Panel. Click Programs, and select “Turn Windows features on or off.” This will bring up a list of Windows Features. Scroll down until you see “Telnet Client,” and put a check in that box. Click “OK.” [2]
    • Windows 10: Right-click the Start menu and select Programs and Features. Click “Turn Windows features on or off” in the left menu. In the list that pops up, put a check in the box next to “Telnet client” and click “OK.”
  2. This is a little different between Windows and Mac.
    • Any version of Windows: Press ⊞ Win + R , type cmd , then press ↵ Enter .
    • Mac: In Finder, select “Applications,” then “Utilities.” Double-click the “Terminal” icon. You can also access Terminal by typing it into Launchpad and clicking it.
    Advertisement
  3. Type telnet mail.server.com 25 where "mail.server.com" is the name of the Simple Mail Transfer Protocol (SMTP) server of your email provider (such as smtp-server.austin.rr.com) and 25 is the port number used by the SMTP service. [3]
    • You should receive a reply like "220 mail.server.com.”
    • Port 25 is the port for most mail servers, but some network administrators move SMTP to a different port, like 465 (a secure port) or 587 (for Microsoft Outlook users). Ask your administrator (or check your account information) for the correct port.
    • If you receive an error message, such as "Cannot connect to host on port 25," and you are sure that port 25 is the correct port, the mail server is likely experiencing an issue.
    4. Advertisement
Part 2
Part 2 of 2:

Sending Your Message

PDF download Download Article
  1. The rest of the steps are the same no matter which operating system you're using. Type HELO yourdomain.com where yourdomain.com is the domain name from which you send e-mail. Note that there is only one L in HELO. Press ↵ Enter . [4]
    • You should receive a reply like "250 mail.server.com Hello yourdomain.com pleased to meet you."
    • If you receive no response or an error message, try EHLO instead of HELO . Some servers prefer one to the other.
  2. Type mail from: you@server.com , using your own e-mail address. Make sure there is a space after the mail from: . Press ↵ Enter .
    • You should receive message that says something similar to "250 Sender OK.”
    • If you see an error, double-check that you’re using an e-mail address with the same domain as the server. Your server may not allow you to send a message with your yahoo.com address, for example.
  3. Type rcpt to: friend@friendsdomain.com , where the e-mail address is that of your actual recipient. Press ↵ Enter .
    • You should see a message that says something along the lines of "250 OK – MAIL FROM you@yourdomain.com ".
    • If you receive an error, the e-mail address you are trying to send a message to may be blocked.
  4. You’ll need to enter a few commands to format and send the message.
    • Type data and press ↵ Enter .
    • On the next line, type subject: test and press ↵ Enter twice. Replace “test” with your desired subject.
    • Type your message. When you’re done, press ↵ Enter .
    • Type a single . to end the message, then press ↵ Enter . You should see a message that confirms your message was accepted or queued. This message varies across servers.
    • If you see any sort of error message, write it down and contact your e-mail provider.
  5. Press ↵ Enter . [5]
    6. Advertisement

Community Q&A

Search
Add New Question
  • Question
    Does this process require an internet connection?
    Community Answer
    Only if you are trying to send your email outside of your local network or use an Internet Mail Server for mailing.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 8 Helpful 14
Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Tips

      • Some mail services (such as Hotmail) don’t allow users to send e-mail via telnet.
        Thanks
        Helpful 0 Not Helpful 0
      • Some e-mail clients will filter mail sent in this manner to a user’s spam mailbox. If you’re using this method to test your account, make sure you check the destination user’s spam folder for the test message.
        Thanks
        Helpful 0 Not Helpful 0
      • The same telnet commands work with any telnet software, even on Linux.
        Thanks
        Helpful 0 Not Helpful 0
      Show More Tips
      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Name
      Please provide your name and last initial
      Submit
      Thanks for submitting a tip for review!
      Advertisement

      Warnings

      • Using this method to send harassing or illegal messages could easily catch up with you. System administrators closely monitor their outbound mail servers.
        Thanks
        Helpful 0 Not Helpful 0
      Advertisement

      Things You'll Need

      • Telnet client
      • The address of a mail server capable of relaying mails
      • Valid email address

      You Might Also Like

      6 Easy Steps to Change Your Email Password on Your iPhone
      How to
      to Access Email on a Computer, Phone, or Tablet
      How to
      Find Your Email’s Incoming and Outgoing Mail Servers
      4 Easy Ways to Open an Email Sent to You
      How to
      Ask for Feedback Over Email: Guide, Expert Tips, & More
      How to
      Create Multiple Email Accounts
      Simple Steps to Set Up an Email Address with Gmail, Outlook + More
      How to
      Make an Email Address for Free
      Easy Email Tracing: Find the Location, True Sender, & More
      2 Simple Ways to Send a Text Message to Your Email
      How to
      Create Folders in Gmail and Automatically Add Emails to Them
      How to
      Send Emails to Multiple People Individually: 3 Step-by-Step Methods
      How to
      Choose an Email Address
      How to
      Write a Formal Email
      Advertisement

      References

      1. ↑ https://www.wintips.org/how-to-enable-telnet-client-in-windows-10/
      2. ↑ http://social.technet.microsoft.com/wiki/contents/articles/910.windows-7-enabling-telnet-client.aspx
      3. ↑ https://learn.microsoft.com/en-us/exchange/mail-flow/test-smtp-telnet
      4. ↑ https://prox.dev/sending-emails-with-telnet/
      5. ↑ https://prox.dev/sending-emails-with-telnet/

      About This Article

      In other languages
      Thanks to all authors for creating a page that has been read 1,439,325 times.

      Is this article up to date?

      Advertisement