diff --git a/test/tests/parallel/set1/dovecot_inet_protocol.bats b/test/tests/parallel/set1/dovecot_inet_protocol.bats
deleted file mode 100644
index 5879471d..00000000
--- a/test/tests/parallel/set1/dovecot_inet_protocol.bats
+++ /dev/null
@@ -1,45 +0,0 @@
-load "${REPOSITORY_ROOT}/test/helper/setup"
-load "${REPOSITORY_ROOT}/test/helper/common"
-
-BATS_TEST_NAME_PREFIX='[Dovecot] (protocols) '
-CONTAINER1_NAME='dms-test_dovecot_protocols_all'
-CONTAINER2_NAME='dms-test_dovecot_protocols_ipv4'
-CONTAINER3_NAME='dms-test_dovecot_protocols_ipv6'
-
-function teardown() { _default_teardown ; }
-
-@test "dual-stack IP configuration" {
-  export CONTAINER_NAME=${CONTAINER1_NAME}
-  local CUSTOM_SETUP_ARGUMENTS=(--env DOVECOT_INET_PROTOCOLS=)
-
-  _init_with_defaults
-  _common_container_setup 'CUSTOM_SETUP_ARGUMENTS'
-
-  _run_in_container grep '^#listen = \*, ::' /etc/dovecot/dovecot.conf
-  assert_success
-  assert_output '#listen = *, ::'
-}
-
-@test "IPv4 configuration" {
-  export CONTAINER_NAME=${CONTAINER2_NAME}
-  local CUSTOM_SETUP_ARGUMENTS=(--env DOVECOT_INET_PROTOCOLS=ipv4)
-
-  _init_with_defaults
-  _common_container_setup 'CUSTOM_SETUP_ARGUMENTS'
-
-  _run_in_container grep '^listen = \*$' /etc/dovecot/dovecot.conf
-  assert_success
-  assert_output 'listen = *'
-}
-
-@test "IPv6 configuration" {
-  export CONTAINER_NAME=${CONTAINER3_NAME}
-  local CUSTOM_SETUP_ARGUMENTS=(--env DOVECOT_INET_PROTOCOLS=ipv6)
-
-  _init_with_defaults
-  _common_container_setup 'CUSTOM_SETUP_ARGUMENTS'
-
-  _run_in_container grep '^listen = \[::\]$' /etc/dovecot/dovecot.conf
-  assert_success
-  assert_output 'listen = [::]'
-}
diff --git a/test/tests/parallel/set1/network_inet_protocols.bats b/test/tests/parallel/set1/network_inet_protocols.bats
new file mode 100644
index 00000000..41a1ec78
--- /dev/null
+++ b/test/tests/parallel/set1/network_inet_protocols.bats
@@ -0,0 +1,76 @@
+load "${REPOSITORY_ROOT}/test/helper/setup"
+load "${REPOSITORY_ROOT}/test/helper/common"
+
+# ENV support for restricting network types that Dovecot and Postfix listen on/
+# PRs:
+# DOVECOT_INET_PROTOCOLS: https://github.com/docker-mailserver/docker-mailserver/pull/2358
+# POSTFIX_INET_PROTOCOLS: https://github.com/docker-mailserver/docker-mailserver/pull/1505
+
+# Docs (upstream):
+# https://doc.dovecot.org/settings/core/#core_setting-listen
+# https://www.postfix.org/postconf.5.html#inet_protocols
+
+BATS_TEST_NAME_PREFIX='[Network] (ENV *_INET_PROTOCOLS) '
+CONTAINER1_NAME='dms-test_inet-protocols_all'
+CONTAINER2_NAME='dms-test_inet-protocols_ipv4'
+CONTAINER3_NAME='dms-test_inet-protocols_ipv6'
+
+function teardown() { _default_teardown ; }
+
+@test "should configure for dual-stack IP by default" {
+  export CONTAINER_NAME=${CONTAINER1_NAME}
+  # Unset (default) should be equivalent to 'all':
+  local CUSTOM_SETUP_ARGUMENTS=(
+    --env DOVECOT_INET_PROTOCOLS=''
+    --env POSTFIX_INET_PROTOCOLS=''
+  )
+
+  _init_with_defaults
+  _common_container_setup 'CUSTOM_SETUP_ARGUMENTS'
+
+  _run_in_container grep '^#listen =' /etc/dovecot/dovecot.conf
+  assert_success
+  assert_output '#listen = *, ::'
+
+  _run_in_container postconf inet_protocols
+  assert_success
+  assert_output 'inet_protocols = all'
+}
+
+@test "should configure for IPv4-only" {
+  export CONTAINER_NAME=${CONTAINER2_NAME}
+  local CUSTOM_SETUP_ARGUMENTS=(
+    --env DOVECOT_INET_PROTOCOLS='ipv4'
+    --env POSTFIX_INET_PROTOCOLS='ipv4'
+  )
+
+  _init_with_defaults
+  _common_container_setup 'CUSTOM_SETUP_ARGUMENTS'
+
+  _run_in_container grep '^listen =' /etc/dovecot/dovecot.conf
+  assert_success
+  assert_output 'listen = *'
+
+  _run_in_container postconf inet_protocols
+  assert_success
+  assert_output 'inet_protocols = ipv4'
+}
+
+@test "should configure for IPv6-only networks" {
+  export CONTAINER_NAME=${CONTAINER3_NAME}
+  local CUSTOM_SETUP_ARGUMENTS=(
+    --env DOVECOT_INET_PROTOCOLS='ipv6'
+    --env POSTFIX_INET_PROTOCOLS='ipv6'
+  )
+
+  _init_with_defaults
+  _common_container_setup 'CUSTOM_SETUP_ARGUMENTS'
+
+  _run_in_container grep '^listen =' /etc/dovecot/dovecot.conf
+  assert_success
+  assert_output 'listen = [::]'
+
+  _run_in_container postconf inet_protocols
+  assert_success
+  assert_output 'inet_protocols = ipv6'
+}
diff --git a/test/tests/serial/mail_postfix_inet.bats b/test/tests/serial/mail_postfix_inet.bats
deleted file mode 100644
index 22656aa9..00000000
--- a/test/tests/serial/mail_postfix_inet.bats
+++ /dev/null
@@ -1,80 +0,0 @@
-load "${REPOSITORY_ROOT}/test/test_helper/common"
-
-# Test case
-# ---------
-# POSTFIX_INET_PROTOCOLS value is set
-
-@test "checking postfix: inet default" {
-  local PRIVATE_CONFIG
-  PRIVATE_CONFIG=$(duplicate_config_for_container . )
-
-  docker run -d --name mail_postfix_inet_default \
-    -v "${PRIVATE_CONFIG}":/tmp/docker-mailserver \
-    -v "$(pwd)/test/test-files":/tmp/docker-mailserver-test:ro \
-    -h mail.my-domain.com -t "${NAME}"
-
-  teardown() { docker rm -f mail_postfix_inet_default; }
-
-  wait_for_finished_setup_in_container mail_postfix_inet_default
-
-  run docker exec mail_postfix_inet_default postconf inet_protocols
-  assert_output "inet_protocols = all"
-  assert_success
-}
-
-@test "checking postfix: inet all" {
-  local PRIVATE_CONFIG
-  PRIVATE_CONFIG=$(duplicate_config_for_container . )
-
-  docker run -d --name mail_postfix_inet_all \
-    -v "${PRIVATE_CONFIG}":/tmp/docker-mailserver \
-    -v "$(pwd)/test/test-files":/tmp/docker-mailserver-test:ro \
-    -e POSTFIX_INET_PROTOCOLS=all \
-    -h mail.my-domain.com -t "${NAME}"
-
-  teardown() { docker rm -f mail_postfix_inet_all; }
-
-  wait_for_finished_setup_in_container mail_postfix_inet_all
-
-  run docker exec mail_postfix_inet_all postconf inet_protocols
-  assert_output "inet_protocols = all"
-  assert_success
-}
-
-@test "checking postfix: inet ipv4" {
-  local PRIVATE_CONFIG
-  PRIVATE_CONFIG=$(duplicate_config_for_container . )
-
-  docker run -d --name mail_postfix_inet_ipv4 \
-    -v "${PRIVATE_CONFIG}":/tmp/docker-mailserver \
-    -v "$(pwd)/test/test-files":/tmp/docker-mailserver-test:ro \
-    -e POSTFIX_INET_PROTOCOLS=ipv4 \
-    -h mail.my-domain.com -t "${NAME}"
-
-  teardown() { docker rm -f mail_postfix_inet_ipv4; }
-
-  wait_for_finished_setup_in_container mail_postfix_inet_ipv4
-
-  run docker exec mail_postfix_inet_ipv4 postconf inet_protocols
-  assert_output "inet_protocols = ipv4"
-  assert_success
-}
-
-@test "checking postfix: inet ipv6" {
-  local PRIVATE_CONFIG
-  PRIVATE_CONFIG=$(duplicate_config_for_container . )
-
-  docker run -d --name mail_postfix_inet_ipv6 \
-    -v "${PRIVATE_CONFIG}":/tmp/docker-mailserver \
-    -v "$(pwd)/test/test-files":/tmp/docker-mailserver-test:ro \
-    -e POSTFIX_INET_PROTOCOLS=ipv6 \
-    -h mail.my-domain.com -t "${NAME}"
-
-  teardown() { docker rm -f mail_postfix_inet_ipv6; }
-
-  wait_for_finished_setup_in_container mail_postfix_inet_ipv6
-
-  run docker exec mail_postfix_inet_ipv6 postconf inet_protocols
-  assert_output "inet_protocols = ipv6"
-  assert_success
-}