diff --git a/changes/bug2470 b/changes/bug2470
new file mode 100644
index 0000000000..8ff97b7bca
--- /dev/null
+++ b/changes/bug2470
@@ -0,0 +1,5 @@
+  o Major bugfixes:
+    - If relays set RelayBandwidthBurst but not RelayBandwidthRate,
+      Tor would ignore their RelayBandwidthBurst setting,
+      potentially using more bandwidth than expected. Bugfix on
+      0.2.0.1-alpha. Reported by Paul Wouters. Fixes bug 2470.
diff --git a/src/or/config.c b/src/or/config.c
index 5aca2256ff..eae92b2408 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -3345,6 +3345,11 @@ options_validate(or_options_t *old_options, or_options_t *options,
                            "PerConnBWBurst", msg) < 0)
     return -1;
 
+  if (options->RelayBandwidthRate && !options->RelayBandwidthBurst)
+    options->RelayBandwidthBurst = options->RelayBandwidthRate;
+  if (options->RelayBandwidthBurst && !options->RelayBandwidthRate)
+    options->RelayBandwidthRate = options->RelayBandwidthBurst;
+
   if (server_mode(options)) {
     if (options->BandwidthRate < ROUTER_REQUIRED_MIN_BANDWIDTH) {
       tor_asprintf(msg,
@@ -3373,9 +3378,6 @@ options_validate(or_options_t *old_options, or_options_t *options,
     }
   }
 
-  if (options->RelayBandwidthRate && !options->RelayBandwidthBurst)
-    options->RelayBandwidthBurst = options->RelayBandwidthRate;
-
   if (options->RelayBandwidthRate > options->RelayBandwidthBurst)
     REJECT("RelayBandwidthBurst must be at least equal "
            "to RelayBandwidthRate.");