diff --git a/Dockerfile b/Dockerfile
index 56936f6..0e60e6d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,8 +13,6 @@ RUN make build-nogui
 
 FROM alpine:edge
 ENV LANG C.UTF-8
-ENV SMTP_PORT 25
-ENV IMAP_PORT 143
 COPY --from=build /usr/src/proton-bridge/Desktop-Bridge /bin/protonmail-bridge
 RUN apk add --no-cache \
       libsecret \
@@ -27,5 +25,7 @@ COPY initproton /bin/
 RUN chmod +x /bin/initproton
 COPY gpgparams /tmp/
 WORKDIR /var/lib/proton
+EXPOSE 25/tcp
+EXPOSE 143/tcp
 ENTRYPOINT ["/bin/entrypoint"]
 CMD ["/bin/initproton"]
diff --git a/entrypoint b/entrypoint
index a77367e..6abe4c6 100755
--- a/entrypoint
+++ b/entrypoint
@@ -13,7 +13,7 @@ export HOME=/var/lib/proton
 # The ProtonMail Bridge expects connections from 127.0.0.1. Use socat to
 # redirect incoming connections to localhost. Also, this allows us to use
 # the default SMTP/IMAP ports.
-socat TCP-LISTEN:$SMTP_PORT,fork TCP:127.0.0.1:1025 &
-socat TCP-LISTEN:$IMAP_PORT,fork TCP:127.0.0.1:1143 &
+socat TCP-LISTEN:25,fork TCP:127.0.0.1:1025 &
+socat TCP-LISTEN:143,fork TCP:127.0.0.1:1143 &
 
 exec /sbin/su-exec proton "$@"
\ No newline at end of file
diff --git a/initproton b/initproton
index d411fa3..7b7aeeb 100755
--- a/initproton
+++ b/initproton
@@ -3,8 +3,6 @@ set -eufo pipefail
 
 BRIDGE=/bin/protonmail-bridge
 PRINT_INFO=${PRINT_INFO:-""}
-SMTP_PORT=${SMTP_PORT:-"25"}
-IMAP_PORT=${IMAP_PORT:-"143"}
 
 #### INIT
 PASS_FILE=${PASS_FILE:-}