We are running an exchange 2010 server. Everything was working fine till this morning. No changes have been made to the server.
The problem we are having is in recieving external email. We are not recieving anything from external accounts. I have run a test using testexchange.com and recieve:
Testing inbound SMTP mail flow for domain email@example.com. ExRCA failed to test inbound SMTP mail flow. Test Steps Attempting to retrieve DNS MX records for domain domain.com.au. One or more MX records were successfully retrieved from DNS. Testing Mail Exchanger direct.domain.com.au. One or more SMTP tests failed for this Mail Exchanger. Test Steps Attempting to resolve the host name direct.domain.com.au in DNS. The host name resolved successfully. Testing TCP port 25 on host direct.domain.com.au to ensure it's listening and open. The port was opened successfully. Attempting to send a test e-mail message to firstname.lastname@example.org using MX direct.domain.com.au. Delivery of the test message failed. Additional Details The server returned status code -1 - The operation has timed out. Exception details: Message: The operation has timed out. Type: System.Net.Mail.SmtpException Stack trace: at System.Net.Mail.SmtpClient.Send(MailMessage message) at Microsoft.Exchange.Tools.ExRca.Tests.SmtpMessageTest.PerformTestReally()
When I try using Telnet from a remote network I get the following:
telnet direct.domain.com.au 25 220 exchange.domain.com.au Microsoft ESMTP MAIL Service ready at Mon, 11 Feb 2013 12:20:09 + 1100 helo test.com.au 250 exchange.domain.com.au Hello [xxx.xx.xxx.207] mail from: email@example.com 250 2.1.0 Sender OK rcpt to: firstname.lastname@example.org 250 2.1.5 Recipient OK data 354 Start mail input; end with <CRLF>.<CRLF> <CRLF>.<CRLF>
and then it just hangs. I'm not sure if I'm ending the data section wrongly, but whatever I type in there Telnet does not send a response. As you can see, TestExchange.com is getting the same result so I don't think it's something I'm doing wrong.
I've checked the server, there are no errors in the event log. We did have a disk space issue a few weeks ago, but there is still 1.5GB free on the exchange drive. We have installed HUB Transport on another server and have pointed SMTP to it and it is working, but this is not ideal for us.
What else can I do to make our primary hub transport exchange service recieve emails?