Our SBS 2003 Exchange Server is intermittently not receiving external emails. I've run a few incoming tests using https://www.testexchangeconnectivity.com and quite frequently the test fails with the following message: Attempting to send a test e-mail message to xxx@xxx.com using MX xxx.xxx.com. (I've removed the email add & MX server) Delivery of the test message failed. Additional Details The server returned status code -1 - Failure sending mail. Exception details: Message: Failure sending mail. Type: System.Net.Mail.SmtpException Stack trace: at System.Net.Mail.SmtpClient.Send(MailMessage message) at Microsoft.Exchange.Tools.ExRca.Tests.SmtpMessageTest.PerformTestReally() Exception details: Message: Failure sending mail. Type: System.Net.Mail.SmtpException Stack trace: at System.Net.Mail.SmtpClient.Send(MailMessage message) at Microsoft.Exchange.Tools.ExRca.Tests.SmtpMessageTest.PerformTestReally() Exception details: Message: Failure sending mail. Type: System.Net.Mail.SmtpException Stack trace: at System.Net.Mail.SmtpClient.Send(MailMessage message) at Microsoft.Exchange.Tools.ExRca.Tests.SmtpMessageTest.PerformTestReally() I've also started logging the SMTP Virtual Server and I'm getting (what I think) are some unusual entries: 22:14:27 216.157.33.106 - - 0 22:14:27 216.157.33.106 MAIL - 0 22:14:27 216.157.33.106 - - 0 22:14:27 216.157.33.106 RCPT - 0 22:14:27 216.157.33.106 - - 0 22:14:27 216.157.33.106 RSET - 0 22:14:27 216.157.33.106 - - 0 22:14:27 216.157.33.106 QUIT - 0 22:14:29 216.157.33.106 - - 0 It's a default installation, there have been no recent changes to the server config, I' not running any email filtering and this issue started occuring about week ago. In most cases we do receive the emails but they might be delayed an hour or so. Any help would be much apprecaited W

What is between Exchange and the Internet? Do you have multiple MX records in place, even if you have a second "backup" server? The SMTP logs by default don't really show much of use, with the exception of the time, nothing in what you have posted stands out as being odd. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi Simon, Thanks for your response. Exchange > ADSL Router > Internet. We run VOIP and a Website but don't have any issues with these services so I doubt it will be our ADSL Router. I've done all the basics like restarting everything. Yes we have multiple MX records in place. At first I had a second MX record pointing at an A record which ultimately pointed back to the same server but removed this as I thought this could be causing issues but it didn't fix the problem. I now have a second MX record with backup server service. If you want to run some tests send an email to wadebarranceAThotmail.com and I will forward you our DNS details. Thanks. Wade

I suspect that the "backup" MX record is your issue. As far as I am concerned, there is no such thing a backup MX record. All MX records (no matter what the cost) are equal. If the server is in the MX records then it will receive email. I would suggest that you remove that second MX record completely from the domain, wait for the DNS records to update and then see if the problem continues. With regards to the router, some routers have SMTP scanning functionality that can get in the way. This wouldn't cause problems with other protocols, just email SMTP. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi, Since the exchange server does not have a public IP and it is connect to the router, you need to set up a forward rule in the router to forward the port 25 traffic to your internal exchange server. Also make sure that your MX record in the external DNS server is pointed to the correct public IP address. You can use the online MX test tool to check it: 1. Access the following link: http://www.mxtoolbox.com/ Please Note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information. 2. Type: MX:yourdomain.com Note: This response contains a reference to a third party World Wide Web site. Microsoft is providing this information as a convenience to you. Microsoft does not control these sites and has not tested any software or information found on these sites; therefore, Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. There are inherent dangers in the use of any software found on the Internet, and Microsoft cautions you to make sure that you completely understand the risk before retrieving any software from the Internet. Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Thanks Gen Lin-MSFT

If you prefer to use a test site that doesn't come with a long disclaimer :-), Microsoft have their own. http://exrca.com which goes to https://www.testexchangeconnectivity.com/ Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi Simon, It was the second MX record causing the issue. Thanks for you help. Kind Regards, Wade