diff --git a/docs/authentication.md b/docs/authentication.md
index 8c6fff251..cd96bb929 100644
--- a/docs/authentication.md
+++ b/docs/authentication.md
@@ -78,7 +78,7 @@ server {
   location /v2/ {
     # Do not allow connections from docker 1.5 and earlier
     # docker pre-1.6.0 did not properly set the user agent on ping, catch "Go *" user agents
-    if ($http_user_agent ~ "^(docker\/1\.(3|4|5(?!\.[0-9]-dev))|Go ).*$" ) {
+    if (\$http_user_agent ~ "^(docker\/1\.(3|4|5(?!\.[0-9]-dev))|Go ).*\$" ) {
       return 404;
     }
 
@@ -88,10 +88,10 @@ server {
     add_header 'Docker-Distribution-Api-Version' 'registry/2.0' always;
 
     proxy_pass                          http://docker-registry;
-    proxy_set_header  Host              $http_host;   # required for docker client's sake
-    proxy_set_header  X-Real-IP         $remote_addr; # pass on real client's IP
-    proxy_set_header  X-Forwarded-For   $proxy_add_x_forwarded_for;
-    proxy_set_header  X-Forwarded-Proto $scheme;
+    proxy_set_header  Host              \$http_host;   # required for docker client's sake
+    proxy_set_header  X-Real-IP         \$remote_addr; # pass on real client's IP
+    proxy_set_header  X-Forwarded-For   \$proxy_add_x_forwarded_for;
+    proxy_set_header  X-Forwarded-Proto \$scheme;
     proxy_read_timeout                  900;
   }
 }