diff --git a/pkgs/servers/http/nix-binary-cache/nix-binary-cache.cgi.in b/pkgs/servers/http/nix-binary-cache/nix-binary-cache.cgi.in
index 1afe8854fed1..890e68765b40 100644
--- a/pkgs/servers/http/nix-binary-cache/nix-binary-cache.cgi.in
+++ b/pkgs/servers/http/nix-binary-cache/nix-binary-cache.cgi.in
@@ -10,13 +10,18 @@ KEYNAME=na
 export NIX_REMOTE=daemon
 
 config="${NIX_BINARY_CACHE_CONFIG:-${HTTP_NIX_BINARY_CACHE_CONFIG:-/etc/nix/nix-binary-cache.cgi.conf}}"
-config="$(cd "$(@coreutils@/dirname "$config")"; 
+config="$(cd "$(@coreutils@/dirname "$config")";
   @coreutils@/pwd)/$(@coreutils@/basename "$config")"
 @coreutils@/test -e "$config" && . "$config"
 
 header(){
 	echo "Content-Type: text/plain; charset=utf-8"
-	echo 
+	echo
+}
+
+header404(){
+	echo "Status: 404 Not Found"
+	echo
 }
 
 clean_path() {
@@ -28,12 +33,12 @@ storeq(){
 }
 
 sign(){
-	test -n "$1" && 
-	  @coreutils@/sha256sum | @gnused@/sed -e 's/ .*//' | 
+	test -n "$1" &&
+	  @coreutils@/sha256sum | @gnused@/sed -e 's/ .*//' |
 	  @openssl@/openssl rsautl -sign -inkey "$@" | @coreutils@/base64 -w 0
 }
 
-case "$QUERY_STRING" in 
+case "$QUERY_STRING" in
 	"")
 		header
 		echo "Hello, this is a dynamically-generated Nix binary cache"
@@ -61,9 +66,9 @@ case "$QUERY_STRING" in
 			echo "Compression: $COMPRESSION"
 			echo "NarHash: $(storeq --hash "$path")"
 			echo "NarSize: $(storeq --size "$path")"
-			echo "References: $(storeq --references "$path" | 
+			echo "References: $(storeq --references "$path" |
 			  @coreutils@/tac | clean_path )"
-			echo "Deriver: $(storeq --deriver "$path" | 
+			echo "Deriver: $(storeq --deriver "$path" |
 			  clean_path )"
 			)"
 			signature="$(echo "$info" | sign "$KEY")"
@@ -72,6 +77,7 @@ case "$QUERY_STRING" in
 			echo "Signature: 1;$KEYNAME;$signature"
 
 		else
+			header404
 			exit 1
 		fi
 		;;
@@ -81,6 +87,7 @@ case "$QUERY_STRING" in
 			header
 			@nix@/nix-store --dump "$path" | @xz@/xz
 		else
+			header404
 			exit 1
 		fi
 		;;
@@ -91,6 +98,7 @@ case "$QUERY_STRING" in
 			header
 			@nix@/nix-store --dump "$path" | @bzip2@/bzip2
 		else
+			header404
 			exit 1
 		fi
 		;;