Testing Mail Servers

Testing Mail Servers

Testing Mail Servers

  • Use MX Toolbox SMTP Diagnostics to test if an email server is running
  • This test will do the following:
    • Connects to the designated mail server via SMTP
    • Determines whether the mail server is an open relay
    • Verifies whether the mail server has a reverse DNS (PTR) record
    • Verifies whether the mail server supports Transport Layer Security (TLS) 
      • TLS is the successor to Secure Sockets Layer (SSL)
      • The TLS and SSL protocols enable secure communications over the Internet
    • Evaluates the connection time and transaction time of the mail server
  • If you don't know the address of the mail server, begin with an MX Lookup

Troubleshooting Incoming Mail Issues

  • Verify your recipient policies are configured correctly
  • Verify your mail server is configured to accept Internet mail on TCP port 25 from anonymous connections
  • Verify your firewall has an incoming rule that accepts connections from TCP port 25
  • Verify a mail exchange (MX) record exists for your domain on an Internet DNS server
  • Verify the MX record points to the externally facing Internet domain of your mail server
  • Verify your mail server is accessible to remote mail servers on the Internet

Troubleshooting Outgoing Mail Issues

  • Verify your mail server that sends Internet mail is configured to use TCP port 25
  • Verify at least one connector contains an address space of * for all external domains when you are using SMTP connectors
  • Verify your mail server's DNS settings are correct and that it is able to resolve external DNS names

Installing Telnet on a Windows Machine

  • Use Add/Remove Programs in the Control Panel to install Telnet
Add and Remove Features Window

Using Telnet to Test SMTP Communication

  • Open a command prompt and type "telnet /?" to view the telnet options
  • Type "telnet" at the command prompt and press <Enter>
  • Type "SET LOCALECHO" at the Telnet prompt to view the responses to the commands
  • Type "o <your mail server domain> 25, and then press ENTER
  • If Telnet is unable to make a connection, type "netstat -an |find /i "listening"" at a regular command prompt on the mail server to see if it is listening on port 25
  • You may need to point to the private IP address of the server instead of the localhost (127.0.0.1) when the mail server is on the same machine as the Sitecore site

Sources