Note that bandwidth-limit options only affect TCP data.

changes/bug17170

@@ -0,0 +1,3 @@
+  o Documentation:
+    - Note that bandwidth-limiting options don't affect TCP headers or DNS.
+      Closes ticket 17170.

doc/tor.1.txt

@@ -184,6 +184,9 @@ GENERAL OPTIONS
     relay (that is, 600 kbits) or 50 KBytes for a bridge (400 kbits) -- but of
     course, more is better; we recommend at least 250 KBytes (2 mbits) if
     possible.  (Default: 1 GByte) +
+ +
+    Note that this option, and other bandwidth-limiting options, apply to TCP
+    data only: They do not count TCP headers or DNS traffic. +
  +
     With this option, and in other options that take arguments in bytes,
     KBytes, and so on, other formats are also supported. Notably, "KBytes" can