diff --git a/tor-relay/Dockerfile b/tor-relay/Dockerfile
index a28125b..e55a25e 100644
--- a/tor-relay/Dockerfile
+++ b/tor-relay/Dockerfile
@@ -34,13 +34,14 @@ COPY torrc.exit /etc/tor/torrc.exit
 
 # copy the run script
 COPY run.sh /run.sh
-RUN chmod u+rwx /run.sh
+RUN chmod ugo+rx /run.sh
 
 # default environment variables
 ENV RELAY_NICKNAME hacktheplanet
 ENV RELAY_TYPE middle
 ENV RELAY_BANDWIDTH_RATE 100 KBytes
 ENV RELAY_BANDWIDTH_BURST 200 KBytes
+ENV RELAY_PORT 9001
 
 # make sure files are owned by tor user
 RUN chown -R tor /etc/tor
diff --git a/tor-relay/run.sh b/tor-relay/run.sh
index f0b8efb..08a3a9d 100644
--- a/tor-relay/run.sh
+++ b/tor-relay/run.sh
@@ -9,6 +9,7 @@ for relaytype in bridge middle exit; do
 	sed -i 's/${CONTACT_EMAIL}/'"$CONTACT_EMAIL"'/g' "/etc/tor/torrc.$relaytype"
 	sed -i 's/${RELAY_BANDWIDTH_RATE}/'"$RELAY_BANDWIDTH_RATE"'/g' "/etc/tor/torrc.$relaytype"
 	sed -i 's/${RELAY_BANDWIDTH_BURST}/'"$RELAY_BANDWIDTH_BURST"'/g' "/etc/tor/torrc.$relaytype"
+	sed -i 's/${RELAY_PORT}/'"$RELAY_PORT"'/g' "/etc/tor/torrc.$relaytype"
 done
 
 exec tor -f /etc/tor/torrc.${RELAY_TYPE}
diff --git a/tor-relay/torrc.bridge b/tor-relay/torrc.bridge
index 9361842..6d85d2d 100644
--- a/tor-relay/torrc.bridge
+++ b/tor-relay/torrc.bridge
@@ -80,7 +80,7 @@
 ## See https://www.torproject.org/docs/tor-doc-relay for details.
 
 ## Required: what port to advertise for incoming Tor connections.
-ORPort 9001
+ORPort ${RELAY_PORT}
 ## If you want to listen on a port other than the one advertised in
 ## ORPort (e.g. to advertise 443 but bind to 9090), you can do it as
 ## follows.  You'll need to do ipchains or other port forwarding
diff --git a/tor-relay/torrc.exit b/tor-relay/torrc.exit
index 3f5e8ac..bab1bbf 100644
--- a/tor-relay/torrc.exit
+++ b/tor-relay/torrc.exit
@@ -80,7 +80,7 @@
 ## See https://www.torproject.org/docs/tor-doc-relay for details.
 
 ## Required: what port to advertise for incoming Tor connections.
-ORPort 9001
+ORPort ${RELAY_PORT}
 ## If you want to listen on a port other than the one advertised in
 ## ORPort (e.g. to advertise 443 but bind to 9090), you can do it as
 ## follows.  You'll need to do ipchains or other port forwarding
diff --git a/tor-relay/torrc.middle b/tor-relay/torrc.middle
index 528d4c3..4c2fe19 100644
--- a/tor-relay/torrc.middle
+++ b/tor-relay/torrc.middle
@@ -80,7 +80,7 @@
 ## See https://www.torproject.org/docs/tor-doc-relay for details.
 
 ## Required: what port to advertise for incoming Tor connections.
-ORPort 9001
+ORPort ${RELAY_PORT}
 ## If you want to listen on a port other than the one advertised in
 ## ORPort (e.g. to advertise 443 but bind to 9090), you can do it as
 ## follows.  You'll need to do ipchains or other port forwarding