diff -Naur cyrus-imapd-2.3.16.orig/imap/backend.c cyrus-imapd-2.3.16/imap/backend.c
--- cyrus-imapd-2.3.16.orig/imap/backend.c	2009-04-23 12:10:05.000000000 -0500
+++ cyrus-imapd-2.3.16/imap/backend.c	2010-03-30 15:58:22.000000000 -0500
@@ -93,7 +93,7 @@
 
     resp = (automatic == AUTO_BANNER) ? prot->banner.resp : prot->capa_cmd.resp;
 
-    if (!automatic) {
+    if (!automatic && strcmp(prot->sasl_service, "csync")) {
 	/* no capability command */
 	if (!prot->capa_cmd.cmd) return NULL;
 	
@@ -449,7 +449,8 @@
     if ((server[0] != '/') ||
 	(strcmp(prot->sasl_service, "lmtp") &&
 	 strcmp(prot->sasl_service, "csync"))) {
-	char *mlist = xstrdup(mechlist); /* backend_auth is destructive */
+        char *mlist = NULL;
+	if (mechlist) mlist = xstrdup(mechlist); /* backend_auth is destructive */
 
 	if ((r = backend_authenticate(ret, prot, &mlist, userid,
 				      cb, auth_status))) {