Merge branch 'master' into develop

1 files changed, 12 insertions, 5 deletions

diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml

index fa2bccd5ef..84337a7c72 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -548,11 +548,12 @@ uploads_path: "DATADIR/uploads"
 #    height: 600
 #    method: scale
 
-# Is the preview URL API enabled?  If enabled, you *must* specify
-# an explicit url_preview_ip_range_blacklist of IPs that the spider is
-# denied from accessing.
+# Is the preview URL API enabled?
 #
-#url_preview_enabled: false
+# 'false' by default: uncomment the following to enable it (and specify a
+# url_preview_ip_range_blacklist blacklist).
+#
+#url_preview_enabled: true
 
 # List of IP address CIDR ranges that the URL preview spider is denied
 # from accessing.  There are no defaults: you must explicitly
@@ -562,6 +563,12 @@ uploads_path: "DATADIR/uploads"
 # synapse to issue arbitrary GET requests to your internal services,
 # causing serious security issues.
 #
+# (0.0.0.0 and :: are always blacklisted, whether or not they are explicitly
+# listed here, since they correspond to unroutable addresses.)
+#
+# This must be specified if url_preview_enabled is set. It is recommended that 
+# you uncomment the following list as a starting point.
+#
 #url_preview_ip_range_blacklist:
 #  - '127.0.0.0/8'
 #  - '10.0.0.0/8'
@@ -572,7 +579,7 @@ uploads_path: "DATADIR/uploads"
 #  - '::1/128'
 #  - 'fe80::/64'
 #  - 'fc00::/7'
-#
+
 # List of IP address CIDR ranges that the URL preview spider is allowed
 # to access even if they are specified in url_preview_ip_range_blacklist.
 # This is useful for specifying exceptions to wide-ranging blacklisted