Refactor network connection test

scripts/Common/Scripts/wait-network.fish

@@ -3,8 +3,14 @@ function waitNetwork -a witness
     set -l timeout (math 10 \* 60)
     set -l codeFile (mktemp)
 
+    function testNetwork
+        # Ping digitalcourage DNS server
+        # https://digitalcourage.de/
+        ping -q -c1 5.9.164.112 > /dev/null
+    end
+
     if [ -z "$witness" ]
-        if not systemctl --quiet is-active network-online.target
+        if not testNetwork
             tmux new-session -d 'cat /etc/motd; echo "$(tput bold)Please establish an internet connection…$(tput sgr0)"; $SHELL'
             fish (status filename) true &
             set -l pid "$last_pid"
@@ -27,7 +33,7 @@ function waitNetwork -a witness
         while true
             set x (math $x + 1)
 
-            if systemctl --quiet is-active network-online.target
+            if testNetwork
                 tmux kill-session &> /dev/null
                 break
             else