Merge pull request #1853 from rsksmart/public_ip_detection_quickfix

Added fallback dummy IP to Public IP discovery service

rskj-core/src/main/java/org/ethereum/config/SystemProperties.java

@@ -499,11 +499,17 @@ private InetAddress getMyPublicIpFromRemoteService() {
         }
 
         InetAddress bindAddress = getBindAddress();
-        if (bindAddress.isAnyLocalAddress()) {
-            throw new RuntimeException("Wildcard on bind address it's not allowed as fallback for public IP " + bindAddress);
+        if (!bindAddress.isAnyLocalAddress()) {
+            return bindAddress;
         }
 
-        return bindAddress;
+        try {
+            // workaround to provide a last resort fallback to calculate node's public IP
+            // this value is safe because it is not being used in any of the protocols; however, once we implement a better solution to identify actual public IP, this fallback should be removed
+            return InetAddress.getByName("127.0.0.1");
+        } catch (UnknownHostException e) {
+            throw new IllegalStateException("Could not provide a public IP", e);
+        }
     }
 
     private URL publicIpCheckService() throws MalformedURLException {

rskj-core/src/main/resources/reference.conf

@@ -205,6 +205,9 @@ public {
 
     # The URL of a service returning our own public IP as the response body.
     # If multiple IPs are returned separated by commas (e.g Amazon returns X-Forwarded-For values) the last one is used
+    # We have two fallback mechanisms in case this service is not working, in order of precedence:
+    #       1) use bind_address property (only if not local)
+    #       2) use hardcoded address "127.0.0.1" as last resort
     ipCheckService = "https://checkip.amazonaws.com"
 }