diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index 919b0b5a..3a9351b3 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -769,11 +769,18 @@ class HttpCli(object):
                 else:
                     upper = file_sz
 
-                if lower < 0 or lower >= file_sz or upper < 0 or upper > file_sz:
+                if upper > file_sz:
+                    upper = file_sz
+
+                if lower < 0 or lower >= upper:
                     raise Exception()
 
             except:
-                raise Pebkac(400, "invalid range requested: " + hrange)
+                err = "invalid range ({}), size={}".format(hrange, file_sz)
+                self.loud_reply(err, status=416, headers={
+                    "Content-Range": "bytes */{}".format(file_sz)
+                })
+                return True
 
             status = 206
             self.out_headers["Content-Range"] = "bytes {}-{}/{}".format(
diff --git a/copyparty/util.py b/copyparty/util.py
index ceaeabcc..097fcbf8 100644
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -49,6 +49,7 @@ HTTPCODE = {
     404: "Not Found",
     405: "Method Not Allowed",
     413: "Payload Too Large",
+    416: "Requested Range Not Satisfiable",
     422: "Unprocessable Entity",
     500: "Internal Server Error",
     501: "Not Implemented",
diff --git a/docs/notes.sh b/docs/notes.sh
index d756a760..c961ea57 100644
--- a/docs/notes.sh
+++ b/docs/notes.sh
@@ -80,3 +80,22 @@ for d in /usr /var; do find $d -type f -size +30M 2>/dev/null; done | while IFS=
 # py2 on osx
 brew install python@2
 pip install virtualenv
+
+
+##
+## http 206
+
+# az = abcdefghijklmnopqrstuvwxyz
+
+printf '%s\r\n' 'GET /az HTTP/1.1' 'Host: ocv.me' 'Range: bytes=5-10' '' | ncat ocv.me 80 
+# Content-Range: bytes 5-10/26
+# Content-Length: 6
+# fghijk
+
+Range: bytes=0-1    "ab" Content-Range: bytes 0-1/26
+Range: bytes=24-24  "y"  Content-Range: bytes 24-24/26
+Range: bytes=24-25  "yz" Content-Range: bytes 24-25/26
+Range: bytes=24-    "yz" Content-Range: bytes 24-25/26
+Range: bytes=25-29  "z"  Content-Range: bytes 25-25/26
+Range: bytes=26-         Content-Range: bytes */26
+  HTTP/1.1 416 Requested Range Not Satisfiable