1 files changed, 5 insertions, 3 deletions

diff --git a/hosts/sif/default.nix b/hosts/sif/default.nix
index adf6fdeb..ca8c6b83 100644
--- a/hosts/sif/default.nix
+++ b/hosts/sif/default.nix
@@ -85,9 +85,11 @@ in {
         pool nts.ntp.se iburst nts
         server nts.sth1.ntp.se iburst nts
         server nts.sth2.ntp.se iburst nts
-        server ptbtime1.ptb.de iburst nts
-        server ptbtime2.ptb.de iburst nts
-        server ptbtime3.ptb.de iburst nts
+        server ptbtime1.ptb.de prefer iburst nts
+        server ptbtime2.ptb.de prefer iburst nts
+        server ptbtime3.ptb.de prefer iburst nts
+        authselectmode require
+        minsources 2
 
         leapsectz right/UTC