docker: add --rpclisten to start-lnd.sh

To make it possible to communicate over gRPC with an instance
running in Docker we need to expose the correct RPC interface.

docker/lnd/start-lnd.sh

@@ -17,7 +17,7 @@ return() {
 
 # set_default function gives the ability to move the setting of default
 # env variable from docker file to the script thereby giving the ability to the
-# user override it durin container start.
+# user override it during container start.
 set_default() {
     # docker initialized env variables with blank string and we can't just
     # use -z flag as usually.
@@ -45,10 +45,16 @@ DEBUG=$(set_default "$DEBUG" "debug")
 NETWORK=$(set_default "$NETWORK" "simnet")
 CHAIN=$(set_default "$CHAIN" "bitcoin")
 BACKEND="btcd"
+HOSTNAME=$(hostname)
 if [[ "$CHAIN" == "litecoin" ]]; then
     BACKEND="ltcd"
 fi
 
+# CAUTION: DO NOT use the --noseedback for production/mainnet setups, ever!
+# Also, setting --rpclisten to $HOSTNAME will cause it to listen on an IP
+# address that is reachable on the internal network. If you do this outside of
+# docker, this might be a security concern!
+
 exec lnd \
     --noseedbackup \
     "--$CHAIN.active" \
@@ -58,5 +64,6 @@ exec lnd \
     "--$BACKEND.rpchost"="blockchain" \
     "--$BACKEND.rpcuser"="$RPCUSER" \
     "--$BACKEND.rpcpass"="$RPCPASS" \
+    "--rpclisten=$HOSTNAME:10009" \
     --debuglevel="$DEBUG" \
     "$@"