diff --git a/bind_set_renew_tlsa.sh b/bind_set_renew_tlsa.sh
index 3f9457a..116524d 100755
--- a/bind_set_renew_tlsa.sh
+++ b/bind_set_renew_tlsa.sh
@@ -307,7 +307,7 @@ done
 _failed=false
 _hostname=$hostname
 _tmp_hostname=$(echo ${_hostname//\./\\.})
-while ! grep -e "$_tmp_hostname" $ZONES_DECLARATION_FILE > /dev/null 2>&1 ; do
+while ! grep -E "^[[:space:]]*zone[[:space:]]+\"$_tmp_hostname\"" $ZONES_DECLARATION_FILE > /dev/null 2>&1 ; do
    _hostname=${_hostname#*.}
    _tmp_hostname=$(echo ${_hostname//\./\\.})
    if [[ ! $_tmp_hostname =~ \. ]]; then