diff --git a/dns_update.sh b/dns_update.sh
index cc040e9..c739aa6 100755
--- a/dns_update.sh
+++ b/dns_update.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -eux
+
 # First argument is cloudflared config file
 # TODO - make this optional, and check standard locations if absent.
 # Not doing it now because that would require me to remember how to
@@ -18,10 +20,11 @@ fi
 # Second argument is "root domain".
 # If set, only try to update DNS for names that are subdomains of this domain.
 # If not set, try to update all names
+TUNNEL_NAME=$(yq ".tunnel" $CONFIG_FILE_LOCATION);
 if [ $# -gt 1 ]; then
   ROOT_DOMAIN=$2;
-  yq ".ingress[].hostname | select(. != null) | select (. == \"*$ROOT_DOMAIN\")" $CONFIG_FILE_LOCATION | xargs -I {} echo "Would process {}";
+  yq ".ingress[].hostname | select(. != null) | select (. == \"*$ROOT_DOMAIN\")" $CONFIG_FILE_LOCATION | xargs -I {} cloudflared tunnel route dns $TUNNEL_NAME {};
 else
-  yq '.ingress[].hostname | select(. != null)' $CONFIG_FILE_LOCATION | xargs -I {} echo "Would process {}";
+  yq '.ingress[].hostname | select(. != null)' $CONFIG_FILE_LOCATION | xargs -I {} cloudflared tunnel route dns $TUNNEL_NAME {};
 fi