Exchange 2010 550 5.7.1 Unable to relay

Posted on 2011-10-10
Last Modified: 2012-05-12
Hello guys!

On a  SBS 2011, using Exchange 2010, when I do a mail test with telnet I receive the following error: "550 5.7.1 Unable to relay".

Any idea?

Thank you!
Question by:r3helpdesk
    LVL 20

    Expert Comment

    by:Hendrik Wiese
    Have you created a relay connector?

    Please see link below:
    How to Configure a Relay Connector for Exchange Server 2010
    LVL 6

    Accepted Solution

    You wont be able to use telnet to send mails using the default send connector. It requires an authentication! This is by design. You still should be able to send mails to your internal organization using RCPT TO: and the error should not appear.

    As Hendrik said, creating a new send connector will allow you to define some network hosts-range that are able to relay emails to external domains without authentication. This requires a new IP on the server for this connector.


    Author Closing Comment

    Thanks for your reply, this is the solution.

    Featured Post

    Integrate social media with email signatures

    Is your company active on social media? Do you also use email signatures? Including social media icons in your email signature is a great way to get fans for free. Let all your email users know you’re on social media quickly and easily, in a single click.

    Join & Write a Comment

    Suggested Solutions

    Find out how to use dynamic social media in email signatures with this top 10 DOs & DON’Ts.
    Not sure what the best email signature size is? Are you worried about email signature image size? Follow this best practice guide.
    In this video we show how to create an Accepted Domain in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Mail Flow >> Ac…
    how to add IIS SMTP to handle application/Scanner relays into office 365.

    728 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    15 Experts available now in Live!

    Get 1:1 Help Now