diff --git a/include/client.h b/include/client.h
index c54ea2b9..171ddd47 100644
--- a/include/client.h
+++ b/include/client.h
@@ -448,6 +448,7 @@ struct ListClient
 #define CLICAP_EXTENDED_JOIN	0x0008
 #define CLICAP_AWAY_NOTIFY	0x0010
 #define CLICAP_TLS		0x0020
+#define CLICAP_SASL_REAUTH	0x0040
 
 /*
  * flags macros.
diff --git a/modules/m_cap.c b/modules/m_cap.c
index 967c1b7e..a17016df 100644
--- a/modules/m_cap.c
+++ b/modules/m_cap.c
@@ -72,6 +72,7 @@ static struct clicap
 } clicap_list[] = {
 	_CLICAP("multi-prefix",	CLICAP_MULTI_PREFIX, 0, 0, 0),
 	_CLICAP("sasl", CLICAP_SASL, 0, 0, 0),
+	_CLICAP("sasl-reauth", CLICAP_SASL_REAUTH, 0, CLICAP_SASL, 0),
 	_CLICAP("account-notify", CLICAP_ACCOUNT_NOTIFY, 0, 0, 0),
 	_CLICAP("extended-join", CLICAP_EXTENDED_JOIN, 0, 0, 0),
 	_CLICAP("away-notify", CLICAP_AWAY_NOTIFY, 0, 0, 0),
diff --git a/modules/m_sasl.c b/modules/m_sasl.c
index 9b139951..852a88e0 100644
--- a/modules/m_sasl.c
+++ b/modules/m_sasl.c
@@ -43,7 +43,7 @@
 #include "s_newconf.h"
 #include "s_conf.h"
 
-static int mr_authenticate(struct Client *, struct Client *, int, const char **);
+static int m_authenticate(struct Client *, struct Client *, int, const char **);
 static int me_sasl(struct Client *, struct Client *, int, const char **);
 
 static void abort_sasl(struct Client *);
@@ -51,7 +51,7 @@ static void abort_sasl_exit(hook_data_client_exit *);
 
 struct Message authenticate_msgtab = {
 	"AUTHENTICATE", 0, 0, 0, MFLG_SLOW,
-	{{mr_authenticate, 2}, mg_reg, mg_ignore, mg_ignore, mg_ignore, mg_reg}
+	{{m_authenticate, 2}, {m_authenticate, 2}, mg_ignore, mg_ignore, mg_ignore, {m_authenticate, 2}}
 };
 struct Message sasl_msgtab = {
 	"SASL", 0, 0, 0, MFLG_SLOW,
@@ -70,7 +70,7 @@ mapi_hfn_list_av1 sasl_hfnlist[] = {
 DECLARE_MODULE_AV1(sasl, NULL, NULL, sasl_clist, NULL, sasl_hfnlist, "$Revision: 1409 $");
 
 static int
-mr_authenticate(struct Client *client_p, struct Client *source_p,
+m_authenticate(struct Client *client_p, struct Client *source_p,
 	int parc, const char *parv[])
 {
 	struct Client *agent_p = NULL;
@@ -80,6 +80,12 @@ mr_authenticate(struct Client *client_p, struct Client *source_p,
 	if(!IsCapable(source_p, CLICAP_SASL))
 		return 0;
 
+	if(IsRegisteredUser(source_p) && !IsCapable(source_p, CLICAP_SASL_REAUTH))
+	{
+		sendto_one(source_p, form_str(ERR_ALREADYREGISTRED), me.name, source_p->name);
+		return 0;
+	}
+
 	if (strlen(client_p->id) == 3)
 	{
 		exit_client(client_p, client_p, client_p, "Mixing client and server protocol");