[CORD-1715] The dest udp port for DHCP reply packets should be 68

Change-Id: I57ca054b452fda7e80da3c2c46e65fe14efd25d8
diff --git a/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/Dhcp4HandlerImpl.java b/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/Dhcp4HandlerImpl.java
index 39e53ff..2ef43b7 100644
--- a/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/Dhcp4HandlerImpl.java
+++ b/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/Dhcp4HandlerImpl.java
@@ -722,7 +722,10 @@
             udpPacket.setDestinationPort(UDP.DHCP_CLIENT_PORT);
         } else {
             // forward to another dhcp relay
-            udpPacket.setDestinationPort(UDP.DHCP_SERVER_PORT);
+            // FIXME: Currently we assume the DHCP comes from a L2 relay with
+            // Option 82, this might not work if DHCP message comes from
+            // L3 relay.
+            udpPacket.setDestinationPort(UDP.DHCP_CLIENT_PORT);
         }
 
         udpPacket.setPayload(dhcpPayload);