The mail_forwarder role still depends on resolvable names in the firewall configuration when allowing incoming connections from the SMTP relay server. This is problematic since when the firewall comes up the name will most likely not be resolvable at that point (the network hasn't been fully brought up).

Instead of resolvable name, the role should instead rely on IP address only.

The following should be done:

• Update the mail_forwarder role.
  • Resolve the SMTP relay server name to an IP address during deployment. This can be done using the getent ahostsv4/ahostsv6 command.
  • Both IPv4 and IPv6 should be covered.
• Update role reference documentation.
• Update usage instructions.
• Update release notes.