MX Check: Troubleshot your SMTP server

Your current IP: Use this IP

Note on Port#: The default SMTP port# is 25 and a regular email server must listen on port 25 to receive emails. However, most ISP block the inbound port 25 to prevent using running email server. If this is your case, you can simply run the email server at different port and use our Mail Redirection Service to forward your emails.

How to manually check if your email server is working?

You can manually telnet to your mail server at port 25 and see if the server is accepting mails for your domain. If the email server is not configured correctly, you usually will get an error message after the rcpt to command.
Make sure you got telnet installed on your machine. The you can issue telnet command to your mail server at its listening port, assumming your email server is listening at port 25
c:\> telnet youremailserver 25
220 .... ESMTP Postfix    If the server is running fine, you should get 220 replys
Then you can issue the following marked commands to the server to see if it response well to your commands:
>> helo yourdomain.com
250 mail.yourdomain.com    The system should replay with 250 code followed by servername
>> mail from: <my@emailaddress.com>    better use a real email address
250 2.1.0 Ok    The system should replay with 250 code followed by servername
>> rcpt to: <addr@yourdomain.com>    Enter a eail that the server will take
250 mail.yourdomain.com    The system should replay with 250 code followed by servername
>> data
354 End data with .    Indicates that you can start entering email content
>> Subject: Test Email Server    After entering the subject, hit Enter for new line
This is a test ........    Enter your email message here.
.    New line with period indicates the end of email message. Hit Enter after period.
>>quit    Enter quit to quit the connection
221 2.0.0 Bye    now it is done. The email will get delivered to the address.
If you email server is configured correctly, you should get the above replay. If it is not setting up correctly, you will likely get errors after rcpt to input. The following are some error replay you might get:
Possible Error Replys After rcpt to
454 4.7.1 <addr@mydomain.com>: Relay access denied The error indicates the server is not take emails for domain mydomain.com
550 5.1.1 <dasfa@dnsexit.com>: Recipient address rejected: User unknown in virtual mailbox table The error indicates the email address does not exist but the server is taking emails for mydomain.com

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