This is still with the box vm having a private IP and the firewall translating public to private using NAT. The only rules I had to add were to allow what is known as “hair-pinning” so that the box VM could reach itself using it’s public IP.
System
✓
All system services are running.
✓
SSH disallows password-based login.
✓
System software is up to date.
✓
Mail-in-a-Box is up to date. You are running version v0.54.
✓
System administrator address exists as a mail alias. [administrator@box.zcloudservices.com ↦ info@zcloudservices.com]
✓
The disk has 84.94 GB space remaining.
✓
System memory is 89% free.
Network
✓
Firewall is active.
✓
Outbound mail (SMTP port 25) is not blocked.
✓
IP address is not blacklisted by zen.spamhaus.org.
box.zcloudservices.com
✓
DNSSEC 'DS' record is set correctly at registrar.
✓
Nameserver glue records are correct at registrar. [ns1/ns2.box.zcloudservices.com ↦ 209.151.200.233]
✓
Domain resolves to box's IP address. [box.zcloudservices.com ↦ 209.151.200.233]
✓
Reverse DNS is set correctly at ISP. [209.151.200.233 ↦ box.zcloudservices.com]
✓
The DANE TLSA record for incoming mail is correct (_25._tcp.box.zcloudservices.com).
✓
Hostmaster contact address exists as a mail alias. [hostmaster@box.zcloudservices.com ↦ administrator@box.zcloudservices.com]
✓
Domain's email is directed to this domain. [box.zcloudservices.com ↦ 10 box.zcloudservices.com]
✓
MTA-STS policy is present.
✓
Postmaster contact address exists as a mail alias. [postmaster@box.zcloudservices.com ↦ administrator@box.zcloudservices.com]
✓
Domain is not blacklisted by dbl.spamhaus.org.
✓
TLS (SSL) certificate is signed & valid. The certificate expires in 85 days on 2022-01-11.
zcloudservices.com
✓
DNSSEC 'DS' record is set correctly at registrar.
✓
Nameservers are set correctly at registrar. [ns1.box.zcloudservices.com; ns2.box.zcloudservices.com]
✓
Domain's email is directed to this domain. [zcloudservices.com ↦ 10 box.zcloudservices.com]
✓
MTA-STS policy is present.
✓
Postmaster contact address exists as a mail alias. [postmaster@zcloudservices.com ↦ administrator@box.zcloudservices.com]
✓
Domain is not blacklisted by dbl.spamhaus.org.
✓
Domain resolves to this box's IP address. [zcloudservices.com ↦ 209.151.200.233]
✓
TLS (SSL) certificate is signed & valid. The certificate expires in 85 days on 2022-01-11.
✓
www.zcloudservices.com: Domain resolves to this box's IP address. [www.zcloudservices.com ↦ 209.151.200.233]
✓
www.zcloudservices.com: TLS (SSL) certificate is signed & valid. The certificate expires in 85 days on 2022-01-11.
✓
autoconfig.zcloudservices.com: Domain resolves to this box's IP address. [autoconfig.zcloudservices.com ↦ 209.151.200.233]
✓
autoconfig.zcloudservices.com: TLS (SSL) certificate is signed & valid. The certificate expires in 85 days on 2022-01-11.
✓
autodiscover.zcloudservices.com: Domain resolves to this box's IP address. [autodiscover.zcloudservices.com ↦ 209.151.200.233]
✓
autodiscover.zcloudservices.com: TLS (SSL) certificate is signed & valid. The certificate expires in 85 days on 2022-01-11.