diff --git a/backplane-dns.lisp b/backplane-dns.lisp
index 6ba8d65..940820b 100644
--- a/backplane-dns.lisp
+++ b/backplane-dns.lisp
@@ -194,7 +194,7 @@
                                     (:= 'domain-id domain-id)
                                     (:= 'type      "SSHFP"))))
            (existing-sshfps (mapcar #'record-content sshfp-records)))
-      (if (not (set-difference existing-sshfps new-sshfps))
+      (if (not (set-difference new-sshfps existing-sshfps))
           t
           (with-transaction ()
             (dolist (record sshfp-records)