Application log filling up with these sorts of errors

Posted on 2011-05-12
Last Modified: 2013-12-27
This is an SMTP protocol error log for virtual server ID 1, connection #507. The remote host "", responded to the SMTP command "xexch50" with "504 5.7.1 Not authorized  ". The full command sent was "XEXCH50 2300 2  ".  This will probably cause the connection to fail.
Question by:tonyswain
    1 Comment
    LVL 11

    Accepted Solution


    xexch50 is sent internally within your exchange org to propagate internal routing info. If they come from outside your Exchange server will deny them because they are not
    implicitly authenticated.

    How to troubleshoot the "504 need to authenticate first" SMTP protocol error

    The second error could be normal if an external system is trying to attempt open relay. If you're experiencing mail flow issues; you will need to get more info as to what the domains or users are affected.

    If you don't have any Exchange servers with a version older than 2007 (2000 and 2003) it's okay to turn off XEXCH50. If you do so, the sending server will send without trying top send XEXCH50 and you won;t see this problem anymore.

    Sanjay Santoki

    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    6 Surprising Benefits of Threat Intelligence

    All sorts of threat intelligence is available on the web. Intelligence you can learn from, and use to anticipate and prepare for future attacks.

    Coaxial cable bending There are several factors that govern the selection of coaxial cable for your Machine to Machine (M2M) application: the location of cable runs, either indoor or outdoor, inside or outside an enclosure, maximum bending and the…
    This subject  of securing wireless devices conjures up visions of your PC or mobile phone connecting to the Internet through some hotspot at Starbucks. But it is so much more than that. Let’s look at the facts: devices#sthash.eoFY7dic.
    This Micro Tutorial will show you how to maximize your wireless card to its maximum capability. This will be demonstrated using Intel(R) Centrino(R) Wireless-N 2230 wireless card on Windows 8 operating system.
    Viewers will learn how to connect to a wireless network using the network security key. They will also learn how to access the IP address and DNS server for connections that must be done manually. After setting up a router, find the network security…

    737 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

    18 Experts available now in Live!

    Get 1:1 Help Now