diff --git a/proto/x11proto/specs/SIAddresses/IPv6.txt b/proto/x11proto/specs/SIAddresses/IPv6.txt
new file mode 100644
index 000000000..4b69a997b
--- /dev/null
+++ b/proto/x11proto/specs/SIAddresses/IPv6.txt
@@ -0,0 +1,11 @@
+ServerInterpreted address definition for type "IPv6":
+
+The X.org Architecture Task Force reserves the ServerInterpreted
+address type of "IPv6" for use with IPv6 literal address formats.
+The syntax for the value will be defined as specified in RFC 3513
+and the IETF RFC to be published based on the current draft at
+http://www.ietf.org/internet-drafts/draft-ietf-ipv6-scoping-arch-00.txt
+This address type specification will be formally issued once the
+IETF IPv6 Working Group issues the corresponding RFC.
+
+Version 0.9, March 2004
diff --git a/proto/x11proto/specs/SIAddresses/Makefile.am b/proto/x11proto/specs/SIAddresses/Makefile.am
new file mode 100644
index 000000000..662776a98
--- /dev/null
+++ b/proto/x11proto/specs/SIAddresses/Makefile.am
@@ -0,0 +1,6 @@
+dist_noinst_DATA = 	\
+	hostname.txt	\
+	IPv6.txt	\
+	localuser.txt	\
+	README
+
diff --git a/proto/x11proto/specs/SIAddresses/README b/proto/x11proto/specs/SIAddresses/README
new file mode 100644
index 000000000..8858529c5
--- /dev/null
+++ b/proto/x11proto/specs/SIAddresses/README
@@ -0,0 +1,4 @@
+This directory contains the specifications of address types for the
+ServerInterpreted address family used in the ChangeHost and ListHosts
+requests in the X11 Protocol.  See Chapter 9 of the X11 Protocol spec
+for more information.
diff --git a/proto/x11proto/specs/SIAddresses/hostname.txt b/proto/x11proto/specs/SIAddresses/hostname.txt
new file mode 100644
index 000000000..64023d7f3
--- /dev/null
+++ b/proto/x11proto/specs/SIAddresses/hostname.txt
@@ -0,0 +1,11 @@
+ServerInterpreted address definition for type "hostname":
+
+A ServerInterpreted address with type "hostname" shall have a value
+representing a hostname as defined in IETF RFC 2396. Due to Mobile IP
+and dynamic DNS, the name service should be consulted at connection
+authentication time.  Clients supporting Internationalized Domain
+Names must convert to ASCII Compatible Encoding as specified in the
+relevant IETF RFC's before use in the X11 protocol.  Note that this
+definition of hostname does not allow use of literal IP addresses.
+
+Version 1.0, March 2004
diff --git a/proto/x11proto/specs/SIAddresses/localuser.txt b/proto/x11proto/specs/SIAddresses/localuser.txt
new file mode 100644
index 000000000..e67ff01de
--- /dev/null
+++ b/proto/x11proto/specs/SIAddresses/localuser.txt
@@ -0,0 +1,20 @@
+Server-interpreted Authentication Types "localuser" and "localgroup":
+
+On systems which can determine in a secure fashion the credentials of a client
+process, the "localuser" and "localgroup" authentication methods provide access
+based on those credentials.  The format of the values provided is platform
+specific.  For POSIX & UNIX platforms, if the value starts with the character
+'#', the rest of the string shall be treated as a decimal uid or gid, otherwise
+the string is defined as a user name or group name.
+
+Systems offering this MUST not simply trust a user supplied value (such as an
+environment variable or IDENT protocol response).  It is expected many systems
+will only support this for clients running on the same host using a local IPC
+transport.
+
+Examples:
+        xhost +SI:localuser:alanc
+        xhost +SI:localuser:#1234
+        xhost +SI:localgroup:wheel
+        xhost +SI:localgroup:#0
+