diff --git a/setup/mscs/msc2946/msc2946.go b/setup/mscs/msc2946/msc2946.go
index 4cffa82ad..a92a16a27 100644
--- a/setup/mscs/msc2946/msc2946.go
+++ b/setup/mscs/msc2946/msc2946.go
@@ -479,7 +479,7 @@ func (w *walker) authorised(roomID, parentRoomID string) (authed, isJoinedOrInvi
 	return w.authorisedServer(roomID), false
 }
 
-// authorisedServer returns true iff the server is joined this room or the room is world_readable
+// authorisedServer returns true iff the server is joined this room or the room is world_readable, public, or knockable
 func (w *walker) authorisedServer(roomID string) bool {
 	// Check history visibility / join rules first
 	hisVisTuple := gomatrixserverlib.StateKeyTuple{
@@ -513,8 +513,21 @@ func (w *walker) authorisedServer(roomID string) bool {
 	// in addition to the actual room ID (but always do the actual one first as it's quicker in the common case)
 	allowJoinedToRoomIDs := []string{roomID}
 	joinRuleEv := queryRoomRes.StateEvents[joinRuleTuple]
+
 	if joinRuleEv != nil {
-		allowJoinedToRoomIDs = append(allowJoinedToRoomIDs, w.restrictedJoinRuleAllowedRooms(joinRuleEv, "m.room_membership")...)
+		rule, ruleErr := joinRuleEv.JoinRule()
+		if ruleErr != nil {
+			util.GetLogger(w.ctx).WithError(ruleErr).WithField("parent_room_id", roomID).Warn("failed to get join rule")
+			return false
+		}
+
+		if rule == gomatrixserverlib.Public || rule == gomatrixserverlib.Knock {
+			return true
+		}
+
+		if rule == gomatrixserverlib.Restricted {
+			allowJoinedToRoomIDs = append(allowJoinedToRoomIDs, w.restrictedJoinRuleAllowedRooms(joinRuleEv, "m.room_membership")...)
+		}
 	}
 
 	// check if server is joined to any allowed room
@@ -537,7 +550,8 @@ func (w *walker) authorisedServer(roomID string) bool {
 	return false
 }
 
-// authorisedUser returns true iff the user is invited/joined this room or the room is world_readable.
+// authorisedUser returns true iff the user is invited/joined this room or the room is world_readable
+// or if the room has a public or knock join rule.
 // Failing that, if the room has a restricted join rule and belongs to the space parent listed, it will return true.
 func (w *walker) authorisedUser(roomID, parentRoomID string) (authed bool, isJoinedOrInvited bool) {
 	hisVisTuple := gomatrixserverlib.StateKeyTuple{
@@ -579,13 +593,20 @@ func (w *walker) authorisedUser(roomID, parentRoomID string) (authed bool, isJoi
 	}
 	joinRuleEv := queryRes.StateEvents[joinRuleTuple]
 	if parentRoomID != "" && joinRuleEv != nil {
-		allowedRoomIDs := w.restrictedJoinRuleAllowedRooms(joinRuleEv, "m.room_membership")
-		// check parent is in the allowed set
 		var allowed bool
-		for _, a := range allowedRoomIDs {
-			if parentRoomID == a {
-				allowed = true
-				break
+		rule, ruleErr := joinRuleEv.JoinRule()
+		if ruleErr != nil {
+			util.GetLogger(w.ctx).WithError(ruleErr).WithField("parent_room_id", parentRoomID).Warn("failed to get join rule")
+		} else if rule == gomatrixserverlib.Public || rule == gomatrixserverlib.Knock {
+			allowed = true
+		} else if rule == gomatrixserverlib.Restricted {
+			allowedRoomIDs := w.restrictedJoinRuleAllowedRooms(joinRuleEv, "m.room_membership")
+			// check parent is in the allowed set
+			for _, a := range allowedRoomIDs {
+				if parentRoomID == a {
+					allowed = true
+					break
+				}
 			}
 		}
 		if allowed {
@@ -615,7 +636,7 @@ func (w *walker) authorisedUser(roomID, parentRoomID string) (authed bool, isJoi
 
 func (w *walker) restrictedJoinRuleAllowedRooms(joinRuleEv *gomatrixserverlib.HeaderedEvent, allowType string) (allows []string) {
 	rule, _ := joinRuleEv.JoinRule()
-	if rule != "restricted" {
+	if rule != gomatrixserverlib.Restricted {
 		return nil
 	}
 	var jrContent gomatrixserverlib.JoinRuleContent