How to allow other email servers on the internet to connect to my exchange server?

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I have an exchange server running on a virtual machine (os: windows server 2012). I’m trying to configure it to be able to send and receive outside emails for my small business. I followed tutorials for its setup and believe exchange is configured correctly. It can send emails to the internet but it can’t receive emails from other email servers on the internet for some reason. Note that I can’t ping the exchange server ip address when I’m on another network and other email clients (e.g. gmail) say their connection was refused when attempting to connect to my exchange server.

Any ideas for how to fix this?

Thank you

Answer

At first, with that information its not very easy to start a deep troubleshooting, so what we can do here is to provide only some basic troubleshooting.

  1. Running a ping do not mean anything, ICMP might be simply blocked by a firewall rule while the server is in fact online and working.

  2. Do your MS Exchange server has an external IP? keep noted that there are public and private IPs, only public (external IPs) could be used in that construct (if you do not perform some strange NAT here).

  3. A much better option instead of a ping would be to check the port from external via telnet. Depending on your Exchange configuration you need to choose the coorect port here. A good start might be port 25

Telnet yourExchangeServerIP 25

  1. Is your MX record correct and pointing to the public IP? Without a correct MX record remote email server will not pick your Exchange server and are then not able to send you an email. As you say other server give you an error message it would be useful to know this error message, so please update your posting and include that.

  2. Can you generate directly an email using telnet and the Server IP from external as explain here?

Attribution
Source : Link , Question Author : 333OnlyHalfEvil , Answer Author : BastianW

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