diff --git a/Dockerfile b/Dockerfile
index e4a64bc..c2da8eb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -30,7 +30,8 @@ FROM crazymax/alpine-s6:${ALPINE_VERSION}-2.2.0.3
 ENV S6_BEHAVIOUR_IF_STAGE2_FAILS="2" \
   TZ="UTC" \
   PUID="1500" \
-  PGID="1500"
+  PGID="1500" \
+  LISTEN_PORT="2500"
 
 RUN apk --update --no-cache add \
     bash \
@@ -54,4 +55,4 @@ COPY rootfs /
 EXPOSE 2500
 
 HEALTHCHECK --interval=10s --timeout=5s \
-  CMD printf 'EHLO localhost\r\nQUIT\r\n' | nc -w 2 127.0.0.1 2500 | grep -q '^250' || exit 1
+  CMD printf 'EHLO localhost\r\nQUIT\r\n' | nc -w 2 127.0.0.1 "$LISTEN_PORT" | grep -q '^250' || exit 1
diff --git a/README.md b/README.md
index 6adbcd2..1cc4170 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,7 @@ linux/s390x
 * `TZ`: Timezone assigned to the container (default `UTC`)
 * `PUID`: Daemon user id (default `1500`)
 * `PGID`: Daemon group id (default `1500`)
+* `LISTEN_PORT`: Container listen port for msmtpd, useful with host, macvlan, or ipvlan networking (default `2500`)
 * `SMTP_HOST`: SMTP relay server to send the mail to. **required**
 * `SMTP_PORT`: Port that the SMTP relay server listens on. Default `25` or `465` if TLS.
 * `SMTP_TLS`: Enable or disable TLS (also known as SSL) for secured connections (`on` or `off`).
@@ -107,7 +108,7 @@ linux/s390x
 
 ## Ports
 
-* `2500`: SMTP relay port
+* `2500`: SMTP relay port, configurable through `LISTEN_PORT`
 
 ## Usage
 
diff --git a/rootfs/etc/cont-init.d/03-create-service.sh b/rootfs/etc/cont-init.d/03-create-service.sh
index 4917eae..aadb26e 100644
--- a/rootfs/etc/cont-init.d/03-create-service.sh
+++ b/rootfs/etc/cont-init.d/03-create-service.sh
@@ -6,6 +6,6 @@ cat > /etc/services.d/msmtpd/run <<EOL
 #!/usr/bin/execlineb -P
 with-contenv
 s6-setuidgid ${PUID}:${PGID}
-msmtpd --interface=0.0.0.0 --port=2500 --command="/usr/bin/msmtp -f %F"
+msmtpd --interface=0.0.0.0 --port=${LISTEN_PORT} --command="/usr/bin/msmtp -f %F"
 EOL
 chmod +x /etc/services.d/msmtpd/run
diff --git a/test/compose.yml b/test/compose.yml
index 010b16e..2e36fd4 100644
--- a/test/compose.yml
+++ b/test/compose.yml
@@ -5,12 +5,13 @@ services:
     image: ${MSMTPD_IMAGE:-crazymax/msmtpd}
     container_name: ${MSMTPD_CONTAINER:-msmtpd}
     ports:
-      - target: 2500
+      - target: 2525
         published: 2500
         protocol: tcp
     environment:
       - "TZ=Europe/Paris"
       - "PUID=1500"
       - "PGID=1500"
+      - "LISTEN_PORT=2525"
       - "SMTP_HOST=smtp.foo.bar"
     restart: always