diff --git a/target/bin/open-dkim b/target/bin/open-dkim
index 9c970812..e0d83bd0 100755
--- a/target/bin/open-dkim
+++ b/target/bin/open-dkim
@@ -98,43 +98,28 @@ do
   esac
 done
 
-DATABASE_ACCOUNTS='/tmp/docker-mailserver/postfix-accounts.cf'
-DATABASE_VIRTUAL='/tmp/docker-mailserver/postfix-virtual.cf'
-DATABASE_VHOST='/tmp/vhost'
-TMP_VHOST='/tmp/vhost.dkim.tmp'
-touch "${TMP_VHOST}"
-if [[ -z ${DOMAINS} ]]
-then
-  # getting domains FROM mail accounts
-  if [[ -f ${DATABASE_ACCOUNTS} ]]
+DATABASE_VHOST='/tmp/vhost.dkim'
+# Prepare a file with one domain per line:
+function _generate_domains_config
+{
+  local TMP_VHOST='/tmp/vhost.dkim.tmp'
+
+  # Generate the default vhost (equivalent to /etc/postfix/vhost),
+  # unless CLI arg DOMAINS provided an alternative list to use instead:
+  if [[ -z ${DOMAINS} ]]
   then
-    # shellcheck disable=SC2034
-    while IFS=$'|' read -r LOGIN PASS
-    do
-      DOMAIN=$(echo "${LOGIN}" | cut -d @ -f2)
-      echo "${DOMAIN}" >>"${TMP_VHOST}"
-    done < <(_get_valid_lines_from_file "${DATABASE_ACCOUNTS}")
+    _obtain_hostname_and_domainname
+    # uses TMP_VHOST:
+    _vhost_collect_postfix_domains
+  else
+    tr ',' '\n' <<< "${DOMAINS}" >"${TMP_VHOST}"
   fi
 
-  # getting domains FROM mail aliases
-  if [[ -f ${DATABASE_VIRTUAL} ]]
-  then
-    # shellcheck disable=SC2034
-    while read -r FROM TO
-    do
-      UNAME=$(echo "${FROM}" | cut -d @ -f1)
-      DOMAIN=$(echo "${FROM}" | cut -d @ -f2)
-
-      [[ ${UNAME} != "${DOMAIN}" ]] && echo "${DOMAIN}" >>"${TMP_VHOST}"
-    done < <(_get_valid_lines_from_file "${DATABASE_VIRTUAL}")
-  fi
-else
-  tr ',' '\n' <<< "${DOMAINS}" >"${TMP_VHOST}"
-fi
-
-sort < "${TMP_VHOST}" | uniq >"${DATABASE_VHOST}"
-rm "${TMP_VHOST}"
+  # uses DATABASE_VHOST + TMP_VHOST:
+  _create_vhost
+}
 
+_generate_domains_config
 if [[ ! -s ${DATABASE_VHOST} ]]
 then
   _log 'warn' 'No entries found, no keys to make'
diff --git a/target/scripts/helpers/accounts.sh b/target/scripts/helpers/accounts.sh
index c4c23a35..dc57945d 100644
--- a/target/scripts/helpers/accounts.sh
+++ b/target/scripts/helpers/accounts.sh
@@ -91,8 +91,6 @@ function _create_accounts
       then
         cp "/tmp/docker-mailserver/${LOGIN}.dovecot.sieve" "/var/mail/${DOMAIN}/${USER}/.dovecot.sieve"
       fi
-
-      echo "${DOMAIN}" >>/tmp/vhost.tmp
     done < <(_get_valid_lines_from_file "${DATABASE_ACCOUNTS}")
 
     _create_dovecot_alias_dummy_accounts
diff --git a/target/scripts/helpers/aliases.sh b/target/scripts/helpers/aliases.sh
index 330fa45b..135de2aa 100644
--- a/target/scripts/helpers/aliases.sh
+++ b/target/scripts/helpers/aliases.sh
@@ -22,17 +22,6 @@ function _handle_postfix_virtual_config
     fi
 
     cp -f "${DATABASE_VIRTUAL}" /etc/postfix/virtual
-
-    # the `to` is important, don't delete it
-    # shellcheck disable=SC2034
-    while read -r FROM TO
-    do
-      UNAME=$(echo "${FROM}" | cut -d @ -f1)
-      DOMAIN=$(echo "${FROM}" | cut -d @ -f2)
-
-      # if they are equal it means the line looks like: "user1     other@domain.tld"
-      [[ ${UNAME} != "${DOMAIN}" ]] && echo "${DOMAIN}" >>/tmp/vhost.tmp
-    done < <(_get_valid_lines_from_file "${DATABASE_VIRTUAL}")
   else
     _log 'debug' "'${DATABASE_VIRTUAL}' not provided - no mail alias/forward created"
   fi
diff --git a/target/scripts/helpers/postfix.sh b/target/scripts/helpers/postfix.sh
index 3d8c555a..0d36670e 100644
--- a/target/scripts/helpers/postfix.sh
+++ b/target/scripts/helpers/postfix.sh
@@ -16,23 +16,73 @@
 # - `postmap` only seems relevant when the lookup type is one of these `file_type` values: http://www.postfix.org/postmap.1.html
 #   Should not be a concern for most types used by `docker-mailserver`: texthash, ldap, pcre, tcp, unionmap, unix.
 #   The only other type in use by `docker-mailserver` is the hash type for /etc/aliases, which `postalias` handles.
+
 function _create_postfix_vhost
 {
   # `main.cf` configures `virtual_mailbox_domains = /etc/postfix/vhost`
   # NOTE: Amavis also consumes this file.
-  : >/etc/postfix/vhost
+  local DATABASE_VHOST='/etc/postfix/vhost'
+  local TMP_VHOST='/tmp/vhost.postfix.tmp'
 
-  # Account and Alias generation will store values in `/tmp/vhost.tmp`.
-  # Filter unique values to the proper config.
-  # NOTE: LDAP stores the domain value set by `docker-mailserver`,
-  # and correctly removes it from `mydestination` in `main.cf` in `setup-stack.sh`.
-  if [[ -f /tmp/vhost.tmp ]]
+  _vhost_collect_postfix_domains
+  _create_vhost
+}
+
+# Filter unique values into a proper DATABASE_VHOST config:
+function _create_vhost
+{
+  : >"${DATABASE_VHOST}"
+
+  if [[ -f ${TMP_VHOST} ]]
   then
-    sort < /tmp/vhost.tmp | uniq >> /etc/postfix/vhost
-    rm /tmp/vhost.tmp
+    sort < "${TMP_VHOST}" | uniq >>"${DATABASE_VHOST}"
+    rm "${TMP_VHOST}"
   fi
 }
 
+# Collects domains from configs (DATABASE_) into TMP_VHOST
+function _vhost_collect_postfix_domains
+{
+  local DATABASE_ACCOUNTS='/tmp/docker-mailserver/postfix-accounts.cf'
+  local DATABASE_VIRTUAL='/tmp/docker-mailserver/postfix-virtual.cf'
+  local DOMAIN UNAME
+
+  # getting domains FROM mail accounts
+  if [[ -f ${DATABASE_ACCOUNTS} ]]
+  then
+    while IFS=$'|' read -r LOGIN _
+    do
+      DOMAIN=$(echo "${LOGIN}" | cut -d @ -f2)
+      echo "${DOMAIN}" >>"${TMP_VHOST}"
+    done < <(_get_valid_lines_from_file "${DATABASE_ACCOUNTS}")
+  fi
+
+  # getting domains FROM mail aliases
+  if [[ -f ${DATABASE_VIRTUAL} ]]
+  then
+    while read -r FROM _
+    do
+      UNAME=$(echo "${FROM}" | cut -d @ -f1)
+      DOMAIN=$(echo "${FROM}" | cut -d @ -f2)
+
+      # if they are equal it means the line looks like: "user1     other@domain.tld"
+      [[ ${UNAME} != "${DOMAIN}" ]] && echo "${DOMAIN}" >>"${TMP_VHOST}"
+    done < <(_get_valid_lines_from_file "${DATABASE_VIRTUAL}")
+  fi
+
+  _vhost_ldap_support
+}
+
+# Add DOMAINNAME (not an ENV, set by `helpers/dns.sh`) to vhost.
+# NOTE: `setup-stack.sh:_setup_ldap` has related logic:
+# - `main.cf:mydestination` setting removes `$mydestination` as an LDAP bugfix.
+# - `main.cf:virtual_mailbox_domains` uses `/etc/postfix/vhost`, but may
+#   conditionally include a 2nd table (ldap:/etc/postfix/ldap-domains.cf).
+function _vhost_ldap_support
+{
+  [[ ${ENABLE_LDAP} -eq 1 ]] && echo "${DOMAINNAME}" >>"${TMP_VHOST}"
+}
+
 # Docs - Postfix lookup table files:
 # http://www.postfix.org/DATABASE_README.html
 #
diff --git a/target/scripts/startup/setup-stack.sh b/target/scripts/startup/setup-stack.sh
index 1dbd84d3..9d84e67d 100644
--- a/target/scripts/startup/setup-stack.sh
+++ b/target/scripts/startup/setup-stack.sh
@@ -360,9 +360,6 @@ function _setup_ldap
 
   configomat.sh "DOVECOT_" "/etc/dovecot/dovecot-ldap.conf.ext"
 
-  # add domainname to vhost
-  echo "${DOMAINNAME}" >>/tmp/vhost.tmp
-
   _log 'trace' 'Enabling Dovecot LDAP authentication'
 
   sed -i -e '/\!include auth-ldap\.conf\.ext/s/^#//' /etc/dovecot/conf.d/10-auth.conf