diff --git a/doc/rfc/index b/doc/rfc/index
index a1450d06b8..684b135cae 100644
--- a/doc/rfc/index
+++ b/doc/rfc/index
@@ -118,3 +118,4 @@
          Dynamic Host Configuration Protocol (DHCP) Information (DHCID RR)
 5155:	DNS Security (DNSSEC) Hashed Authenticated Denial of Existence
 5295:	Host Identity Protocol (HIP) Domain Name System (DNS) Extension
+5507:	Design Choices When Expanding the DNS