How to setup Multiple Domains with one External IP?
Question asked by Archie Quintana - August 25, 2017 at 9:28 AM
Answered
Hi,
 
I would like to know how to setup SmarterMail to host multiple domains with just one external static IP. This is what I have so far:
 
-    I have configured the server where SmarterMail is installed with a static private IP 192.168.10.6
-    I have configured 192.168.10.7 and 192.168.10.8 as secondary private IPs for server where SmarterMail is installed on.
-    I configured in SmarterMail domain mail.domain1.com which is binded to IP 192.168.10.7
-    I configured in SmarterMail domain mail.domain2.com which is binded to IP 192.168.10.8
-    When I telnet internally to IP 192.168.10.6 on port 25,  I get “220 Email-Server" which means good.
-    When I telnet internally to IP 192.168.10.7 on port 25,  I get “220 mail.domain1.com" which means good.
-    When I telnet internally to IP 192.168.10.8 on port 25,  I get “220 mail.domain2.com" which means good.
-    I opened port 25 on my firewall so that traffic on port 25 is routed from the external IP to internal IP 192.168.10.6 (the server where SmarterMail is installed on)
-    When I telnet externally to mail.domain1.com on port 25, I get “220 Email-Server Service Ready” instead of “mail.domain1.com Service Ready” which means no good.
-    When I telnet externally to mail.domain2.com on port 25, I get “220 Email-Server Service Ready” instead of “mail.domain2.com Service Ready” which means no good.
 
These results tell me that the servers are running and ready and that the routing policy for port 25 is working fine as it is routing to the right IP specified in the policy.
 
The goal: I should be able to telnet each of these domains and have it connect to the right server. Can someone help?
 
Thanks,
 
Archie.
 
P.S. Please note that I can only route traffic on port 25 from the external IP to one internal IP.

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Von-Austin See Replied
Employee Post
Archie,
 
I wanted to post in here since you also opened a ticket with us to assist with this issue. I wanted to get the information out on the community in case someone else wants to setup this scenario.
 
In order for each domain to have it's own banner response for example '220 mail.domain1.com' you would need a public IP for each separate banner response due to how the hostnames are mapped within SmarterMail and bound to each IP address.
 
Since you're behind a NAT, you would need multiple WAN IP's to perform a 1:1 mapping for the IP hostnames. 
 
Regardless of banner response, your users across your multiple domains can authenticate to any IP you have listening. So users from domain1.com, domain2.com, domain3.com could all authenticate when connecting to either internal IP address configured within SmarterMail.
 
I hope this helps !
Von See
Technical Support Supervisor
SmarterTools Inc.
(877) 357-6278
www.smartertools.com

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