diff --git a/1/trixie/docker-entrypoint.sh b/1/trixie/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/1/trixie/docker-entrypoint.sh
+++ b/1/trixie/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/3/bookworm/docker-entrypoint.sh b/3/bookworm/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/3/bookworm/docker-entrypoint.sh
+++ b/3/bookworm/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/3/trixie/docker-entrypoint.sh b/3/trixie/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/3/trixie/docker-entrypoint.sh
+++ b/3/trixie/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/3/ubi8/docker-entrypoint.sh b/3/ubi8/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/3/ubi8/docker-entrypoint.sh
+++ b/3/ubi8/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/4/bookworm/docker-entrypoint.sh b/4/bookworm/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/4/bookworm/docker-entrypoint.sh
+++ b/4/bookworm/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/4/trixie/docker-entrypoint.sh b/4/trixie/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/4/trixie/docker-entrypoint.sh
+++ b/4/trixie/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/4/ubi8/docker-entrypoint.sh b/4/ubi8/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/4/ubi8/docker-entrypoint.sh
+++ b/4/ubi8/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/5/bookworm/docker-entrypoint.sh b/5/bookworm/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/5/bookworm/docker-entrypoint.sh
+++ b/5/bookworm/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/5/trixie/docker-entrypoint.sh b/5/trixie/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/5/trixie/docker-entrypoint.sh
+++ b/5/trixie/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/5/ubi8/docker-entrypoint.sh b/5/ubi8/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/5/ubi8/docker-entrypoint.sh
+++ b/5/ubi8/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 87b4677..b1bdf23 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -196,7 +196,7 @@ docker_process_init_files() {
 #    ie: docker_process_sql -f my-file.sql
 #    ie: docker_process_sql <my-file.sql
 docker_process_sql() {
-	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p 5866 --no-password --no-psqlrc )
+	local query_runner=( psql -v ON_ERROR_STOP=1 --username "$IVORYSQL_USER" -p "${PGPORT:-5866}" --no-password --no-psqlrc )
 	if [ -n "$IVORYSQL_DB" ]; then
 		query_runner+=( --dbname "$IVORYSQL_DB" )
 	fi
diff --git a/tests/entrypoint-port.sh b/tests/entrypoint-port.sh
new file mode 100644
index 0000000..593fbe0
--- /dev/null
+++ b/tests/entrypoint-port.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+# Run from the repository root: bash tests/entrypoint-port.sh
+# Stub only database commands; exercise every shipped entrypoint function.
+set -Eeuo pipefail
+for script in docker-entrypoint.sh [0-9]*/*/docker-entrypoint.sh; do
+  for port in '' 6543; do
+    (
+      source "$script"
+      export PGPORT="$port" IVORYSQL_USER=test IVORYSQL_DB=test PGDATA=/tmp/test
+      expected_port=${PGPORT:-5866}
+      psql() {
+        while (( $# )); do
+          if [[ $1 == -p ]]; then
+            [[ $2 == "$expected_port" ]] || {
+              echo "$script: SQL client uses $2 instead of $expected_port" >&2
+              return 1
+            }
+            return
+          fi
+          shift
+        done
+        echo 'SQL client port missing' >&2
+        return 1
+      }
+      pg_ctl() {
+        while (( $# )); do
+          if [[ $1 == -o ]]; then
+            [[ " $2 " == *" -p $expected_port "* ]]
+            return
+          fi
+          shift
+        done
+        return 1
+      }
+      docker_temp_server_start postgres
+      docker_process_sql --command 'SELECT 1'
+    )
+  done
+done
+echo 'All entrypoint client/server port checks passed'