I just setup a Windows 2008 R2 server and am trying to get a basic mail server up and running so that I can send emails from my applications.
I setup a virtual SMTP server in IIS6 and tried doing a local telnet to port 25, which seemed to work fine. There were no errors during this stage and I can see the mail message appear in the Queue folder.
The problem is that mail never leaves the Queue folder. I then tried to telnet to a remote mail server on port 25 but couldn't connect:-
telnet 18.104.22.168 25 Could not open connection to the host, on port 25: Connection failed)
I checked my firewall and there is a default setting to allow all outgoing TCP traffic with no restriction. I even setup a specific rule for outgoing port 25 traffic but to no avail.
I then ran a SmtpDiag.exe command
.\SmtpDiag.exe firstname.lastname@example.org email@example.com
and received the following output
Searching for Exchange external DNS settings. Computer name is WIN-SERVERNAME. Failed to connect to the domain controller. Error: 8007054b Checking SOA for gmail.com. Checking external DNS servers. Checking internal DNS servers. SOA serial number match: Passed. Checking local domain records. Checking MX records using TCP: gmail.com. Checking MX records using UDP: gmail.com. Both TCP and UDP queries succeeded. Local DNS test passed. Checking remote domain records. Checking MX records using TCP: gmail.com. Checking MX records using UDP: gmail.com. Both TCP and UDP queries succeeded. Remote DNS test passed. Checking MX servers listed for firstname.lastname@example.org. Connecting to gmail-smtp-in.l.google.com [22.214.171.124] on port 25. Connecting to the server failed. Error: 10060 Failed to submit mail to gmail-smtp-in.l.google.com.
Is there any other diagnostics I can do to figure out if it's my firewall or something else? I have removed antivirus to make sure that it wasn't causing the problem. Any ideas would be much appreciated.