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Velvet Digest

How do I know if my SMTP server is working?

Author

Christopher Snyder

Updated on April 29, 2026

To test your connection to the SMTP server:
  1. Verify that port 25 (which is the default port used by SMTP) is not blocked by any firewall or anti-virus software.
  2. Obtain the SMTP email server and port number:
  3. Click Start, Run, type CMD and click OK.
  4. At the command prompt, type the following:

.

Moreover, how do I test my SMTP server?

To test the SMTP service, follow these steps:

  1. On a client computer running Windows Server or Windows 10 (with telnet client installed), type. Telnet at a command prompt, and then press ENTER.
  2. At the telnet prompt, type set LocalEcho, press ENTER, and then type open <machinename> 25, and then press ENTER.

Beside above, how do I check my SMTP credentials? To test SMTP authentication via telnet:

  1. In a telnet client such as PuTTY, connect to the SMG appliance: telnet <SMG_IP_address> 587.
  2. Greet the mail server: EHLO mailserver.com.
  3. Tell SMG you want to authenticate with it: AUTH LOGIN.
  4. Paste the base64 encoded username.
  5. Paste the base64 encoded password for the username.

Beside this, how do I test my SMTP port 25?

Here's how to open the command prompt on Windows 98, XP or Vista:

  1. Open the Start menu.
  2. Select Run.
  3. Type cmd.
  4. Press Enter.
  5. Type telnet MAILSERVER 25 (replace MAILSERVER with your mail server (SMTP) which may be something like server.domain.com or mail.yourdomain.com).
  6. Press Enter.

How do I connect to SMTP server?

And here's the standard procedure of SMTP configuration, in four steps:

  1. Select the voice “Account Settings” in your mail client, generally in the “Tools” menu.
  2. Choose the “Outgoing server (SMTP)” voice:
  3. Push the “Add…” button in order to set a new SMTP. A popup window will appear:
  4. Now simply fill the voices as follows:
Related Question Answers

How does SMTP work?

SMTP is part of the application layer of the TCP/IP protocol. Using a process called "store and forward," SMTP moves your email on and across networks. It works closely with something called the Mail Transfer Agent (MTA) to send your communication to the right computer and email inbox.

How do I find my SMTP server name in Outlook?

Outlook for PC
  1. In Outlook, click File.
  2. On the Email tab, double-click on the account you want to connect to HubSpot.
  3. Below Server Information, you can find your incoming mail server (IMAP) and outgoing mail server (SMTP) names.
  4. To find the ports for each server, click More settings >

How do I troubleshoot SMTP problems?

And here's a checklist to understand why you're unable to send emails and troubleshoot any major problem:
  1. Check your internet connection. Yup.
  2. Check your SMTP server details.
  3. Verify all usernames and passwords.
  4. Check your SMTP server connection.
  5. Change your SMTP port.
  6. Control your antivirus or firewall settings.

How do I find my SMTP server for Gmail?

Use these settings:
  1. Gmail SMTP server address: smtp.gmail.com.
  2. Gmail SMTP username: Your Gmail address (for example, [email protected])
  3. Gmail SMTP password: Your Gmail password.
  4. Gmail SMTP port (TLS): 587.
  5. Gmail SMTP port (SSL): 465.
  6. Gmail SMTP TLS/SSL required: Yes.

How do I find my SMTP server in Outlook 365?

The following settings are the official POP, IMAP and SMTP settings provided by Microsoft for Office 365.

Office 365: POP, IMAP and SMTP settings for Office 365.

POP settings Server name: outlook.office365.com Port: 995 Encryption method: SSL
SMTP settings Server name: smtp.office365.com Port: 587 Encryption method: TLS or STARTTLS

How do I find my SMTP username and password?

How can I find out my SMTP User Name and SMTP Password?
  1. Log in to your account in the Secure SMTP Control Panel.
  2. From the top menu select 'SMTP Accounts'.
  3. Select the required SMTP account from the list, and click the 'Edit' button.
  4. On the 'Edit SMTP Account' page you can change your SMTP User Name and SMTP password.
  5. Then click on 'Confirm' after you have made any changes.

How do I telnet to a SMTP server?

Open a Command Prompt window, type telnet , and then press Enter. This command opens the Telnet session. Type set localecho , and then press Enter. This optional command lets you view the characters as you type them, and it might be required for some SMTP servers.

Why is port 25 blocked?

TCP port 25 is frequently blocked by Internet Service Providers (ISPs), as an anti-spam technique since it's used in MX spamming and abuse of open proxy/relay machines. To send email on such ISPs, one must either: connect to your SMTP server at DreamHost on port 587.

What port is 23?

Well-known ports
Port TCP Description
22 Yes, and SCTP Secure Shell (SSH), secure logins, file transfers (scp, sftp) and port forwarding
23 Yes Telnet protocol—unencrypted text communications
25 Yes Simple Mail Transfer Protocol (SMTP), used for email routing between mail servers
37 Yes Time Protocol

What port 25 is used for?

Port 25 is to be used for relaying messages between MTAs (Mail Transfer Agents) or from MSAs (Mail Submission Agents) to MTAs. Port 467 is the port chosen for encrypted connections. Port 587 is the one recommended for message submissions by mail clients to mail servers.

How can I test if a port is open?

Steps
  1. Enter the port. Type the port you want to check (e.g., 22 for SSH) into the "Port to Check" box.
  2. Click Check Port. If the port is open and available, you'll see a confirmation message. If not, you'll see a message that says "Error: I could not see your service on (your IP address) on port (the port number)."

How do you check if ports are blocked?

Checking Windows Firewall for blocked ports
  1. Launch Command Prompt.
  2. Run netstat -a -n.
  3. Check to see if the specific port is listed. If it is, then it means that the server is listening on that port.

What is the port 143?

GRC | Port Authority, for Internet Port 143. Description: Imap protocol is used by eMail clients for the retrieval of their eMail from designated eMail "post office" servers. Imap on port 143 is the newer of the two popular protocols used to retrieve eMail from remote mail servers.

What is port 443 normally used for?

Port 443 is the standard port for all secured HTTP traffic, meaning it's absolutely essential for most modern web activity. Encryption is necessary to protect information, as it makes its way between your computer and a web server.

Is port 25 blocked by my ISP?

The standard port used for SMTP connections is 25. An ISP (Internet Service Provider) may block port 25 in order to prevent spamming by its customers. With port 25 being blocked, you won't be able to host your own mail server at home or work.

Can you ping SMTP server?

When in Command prompt, type ping mail.example.com where mail.example.com is the name or IP address of SMTP server you intend to use. Normally, if SMTP server is reachable, it should reply. If SMTP server is not reachable, the ping request will timeout.

How do I ping a mail server?

How to ping an email address
  1. Enable Telnet. Open the Start menu on your PC or laptop, go to Control Panel. There go to Programs, and then Features.
  2. Find the mail server. In Search at the bottom of PC menu, search for “cmd” and click on a small black box – this opens the command prompt. Type nslookup –type=mx domain.com.