resolved: add support for explicitly forgetting everything we learnt about DNS server feature levels

This adds "systemd-resolve --reset-server-features" for explicitly
forgetting what we learnt. This might be useful for debugging
purposes, and to force systemd-resolved to restart its learning logic
for all DNS servers.

1 files changed, 6 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index ac6f23c37d..bc1a77bf12 100644
--- a/NEWS
+++ b/NEWS
@@ -209,6 +209,12 @@ CHANGES WITH 235:
           too. Note that while the other databases are world-readable
           (i.e. 0644), btmp is not and remains more restrictive.
 
+        * The systemd-resolve tool gained a new --reset-server-features
+          switch. When invoked like this systemd-resolved will forget
+          everything it learnt about the features supported by the configured
+          upstream DNS servers, and restarts the feature probing logic on the
+          next resolver look-up for them at the highest feature level again.
+
         Contributions from: Abdó Roig-Maranges, Alan Jenkins, Alexander
         Kuleshov, Andreas Rammhold, Andrew Jeddeloh, Andrew Soutar, Ansgar
         Burchardt, b1tninja, bengal, Benjamin Berg, Benjamin Robin, Charles