FORUM PLAN UPDATE
Date revision: This forum will remain open to new posts and responses until December 1, 2018. (After that date, you will still be able to view and search the forum.) Also, we're taking a second look at the best place to host future conversation. For now, keep using this forum, and stay tuned for more news.


Jun 9, 2017, 2:13 AM
49 Posts
topic has been resolvedResolved

Configure primary and secondary MX for one server

  • Category: Domino Administrator
  • Platform: Windows
  • Release: 9.0.1
  • Role: Administrator
  • Tags: mail flow,DNS
  • Replies: 3

Hi there,

We have a single Domino server with hostname mail1.acme.com.

We have 2 separate lines from 2 different ISPs that are connected to mail1.acme.com. i.e. 2 public IPs that are NAT to the internal IP of mail1.acme.com

I wanted to do something like this:

Type Preference Hostname IP
MX 10 mail1.acme.com public IP from ISP1
MX 20 mail1.acme.com public IP from ISP2

Create 2 MX records with the same host name.

Then create 2 A records that map the host name to the 2 different public IPs

But the person who manages our DNS (on cloudflare) told me that it is not possible to create 2 A records with the same hostname but different public IPs.

So, it was decided that the secondary MX would have hostname mail2.acme.com and its A record will have the second ISP's public IP.

Mail flow works, with both the primary and secondary.

However, when we use the secondary, we have an SSL error because the hostname in the MX record does not match the hostname in the SSL certificate.

Is there any way around this?

Have any of you had the same issue and how did you set up your system?

Jun 12, 2017, 2:43 AM
105 Posts
A second host

The problem you face is that a Domino server cannot respond as multiple host names depending on the IP.  You will need a second host to do what you want.  If you have a restriction on physical machines then you could look at Domino partitioning to create a second Domino server on the same physical machine.  You could also investigate fronting SMTP with Postfix as I think it can be configured the way you want.

Jun 12, 2017, 5:34 AM
49 Posts
Thanks

Thank you D Porter.

Jun 12, 2017, 5:34 AM
49 Posts
Configure primary and secondary MX for one server

Hi there,

We have a single Domino server with hostname mail1.acme.com.

We have 2 separate lines from 2 different ISPs that are connected to mail1.acme.com. i.e. 2 public IPs that are NAT to the internal IP of mail1.acme.com

I wanted to do something like this:

Type Preference Hostname IP
MX 10 mail1.acme.com public IP from ISP1
MX 20 mail1.acme.com public IP from ISP2

Create 2 MX records with the same host name.

Then create 2 A records that map the host name to the 2 different public IPs

But the person who manages our DNS (on cloudflare) told me that it is not possible to create 2 A records with the same hostname but different public IPs.

So, it was decided that the secondary MX would have hostname mail2.acme.com and its A record will have the second ISP's public IP.

Mail flow works, with both the primary and secondary.

However, when we use the secondary, we have an SSL error because the hostname in the MX record does not match the hostname in the SSL certificate.

Is there any way around this?

Have any of you had the same issue and how did you set up your system?


FORUM PLAN UPDATE
Date revision: This forum will remain open to new posts and responses until December 1, 2018. (After that date, you will still be able to view and search the forum.) Also, we're taking a second look at the best place to host future conversation. For now, keep using this forum, and stay tuned for more news.