diff --git a/Docs/manual.html b/Docs/manual.html
index e4cc1a5..ad4bbec 100644
--- a/Docs/manual.html
+++ b/Docs/manual.html
@@ -223,6 +223,17 @@ This secret will be used in all RADIUS queries.  If this is not set then
 RADIUS queries will fail.
 </LI>
 
+<LI><B>radius_authtypes</B> (string)</BR>
+A comma separated list of supported RADIUS authentication methods
+(<B>pap</B> or <B>chap</B>), in order of preference (default <B>pap</B>).
+</LI>
+
+<LI><B>allow_duplicate_users</B> (boolean)</BR>
+Allow multiple logins with the same username.  If false (the default),
+any prior session with the same username will be dropped when a new
+session is established.
+</LI>
+
 <LI><B>bind_address</B> (ip address)<BR>
 When the tun interface is created, it is assigned the address
 specified here.  If no address is given, 1.1.1.1 is used.  Packets
diff --git a/Docs/startup-config.5 b/Docs/startup-config.5
index 89112d6..cf70f50 100644
--- a/Docs/startup-config.5
+++ b/Docs/startup-config.5
@@ -2,7 +2,7 @@
 .de Id
 .ds Dt \\$4 \\$5
 ..
-.Id $Id: startup-config.5,v 1.8 2005-05-26 12:17:31 bodea Exp $
+.Id $Id: startup-config.5,v 1.9 2005-06-02 04:04:08 bodea Exp $
 .TH STARTUP-CONFIG 5 "\*(Dt" L2TPNS "File Formats and Conventions"
 .SH NAME
 startup\-config \- configuration file for l2tpns
@@ -103,6 +103,11 @@ Secret to be used in RADIUS packets.
 A comma separated list of supported RADIUS authentication methods
 ("pap" or "chap"), in order of preference (default "pap").
 .TP
+.B allow_duplicate_users
+Allow multiple logins with the same username.  If false (the default),
+any prior session with the same username will be dropped when a new
+session is established.
+.TP
 .B bind_address
 When the tun interface is created, it is assigned the address
 specified here.  If no address is given, 1.1.1.1 is used.  Packets
diff --git a/l2tpns.c b/l2tpns.c
index f30ada8..beb6df5 100644
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.105 2005-05-26 12:17:30 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.106 2005-06-02 04:04:07 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -113,6 +113,7 @@ config_descriptt config_values[] = {
 	CONFIG("radius_interim", radius_interim, INT),
 	CONFIG("radius_secret", radiussecret, STRING),
 	CONFIG("radius_authtypes", radius_authtypes_s, STRING),
+	CONFIG("allow_duplicate_users", allow_duplicate_users, BOOL),
 	CONFIG("bind_address", bind_address, IPv4),
 	CONFIG("peer_address", peer_address, IPv4),
 	CONFIG("send_garp", send_garp, BOOL),
@@ -4190,8 +4191,16 @@ int sessionsetup(tunnelidt t, sessionidt s)
 		for (i = 1; i <= config->cluster_highest_sessionid; i++)
 		{
 			if (i == s) continue;
-			if (ip == session[i].ip) sessionkill(i, "Duplicate IP address");
-			if (!session[s].walled_garden && !session[i].walled_garden && strcasecmp(user, session[i].user) == 0)
+			if (!session[s].opened) continue;
+			if (ip == session[i].ip)
+			{
+				sessionkill(i, "Duplicate IP address");
+				continue;
+			}
+
+			if (config->allow_duplicate_users) continue;
+			if (session[s].walled_garden || session[i].walled_garden) continue;
+			if (!strcasecmp(user, session[i].user))
 				sessionkill(i, "Duplicate session for users");
 		}
 	}
diff --git a/l2tpns.h b/l2tpns.h
index 2bc315c..423f105 100644
--- a/l2tpns.h
+++ b/l2tpns.h
@@ -1,5 +1,5 @@
 // L2TPNS Global Stuff
-// $Id: l2tpns.h,v 1.73 2005-05-26 12:17:30 bodea Exp $
+// $Id: l2tpns.h,v 1.74 2005-06-02 04:04:07 bodea Exp $
 
 #ifndef __L2TPNS_H__
 #define __L2TPNS_H__
@@ -458,6 +458,8 @@ typedef struct
 	int		radius_authtypes;
 	int		radius_authprefer;
 
+	int		allow_duplicate_users;		// allow multiple logins with the same username
+
 	in_addr_t	default_dns1, default_dns2;
 
 	unsigned long	rl_rate;			// default throttle rate