diff -brau openl2tp-1.8.o/doc/openl2tp_rpc.4 openl2tp-1.8/doc/openl2tp_rpc.4
--- openl2tp-1.8.o/doc/openl2tp_rpc.4	2011-06-04 10:02:34.000000000 +0200
+++ openl2tp-1.8/doc/openl2tp_rpc.4	2011-06-04 21:17:22.000000000 +0200
@@ -719,6 +719,10 @@
 .B chap_restart
 Retransmission timeout for CHAP challenges. Default=3.
 .TP
+.B clientip_as_ipparam
+Whether or not to pass the remote client ip (connecting IP) as ipparam to pppd
+(similar to to pptpd).
+.TP
 .B pap_max_auth_reqs
 Maximum number of PAP authenticate-request transmissions. Default=10.
 .TP
diff -brau openl2tp-1.8.o/l2tp_common.c openl2tp-1.8/l2tp_common.c
--- openl2tp-1.8.o/l2tp_common.c	2011-06-04 21:00:45.000000000 +0200
+++ openl2tp-1.8/l2tp_common.c	2011-06-04 21:19:46.000000000 +0200
@@ -931,6 +931,7 @@
 	if (OPTSTRING_PTR(pp->remote_name) != NULL) {
 		len += fprintf(file, "  remote name for authentication: %s\n", OPTSTRING(pp->remote_name));
 	}
+	len += fprintf(file, "  clientip as ipparam: %s\n", pp->clientip_as_ipparam ? "YES" : "NO");
 	len += fprintf(file, "  max connect time: %d, max failure count: %d, idle timeout: %d\n",
 		       pp->max_connect_time, pp->max_failure_count, pp->idle_timeout);
 	if (pp->asyncmap != 0) {
diff -brau openl2tp-1.8.o/l2tp_config.c openl2tp-1.8/l2tp_config.c
--- openl2tp-1.8.o/l2tp_config.c	2011-06-04 11:43:03.000000000 +0200
+++ openl2tp-1.8/l2tp_config.c	2011-06-04 21:30:48.000000000 +0200
@@ -3124,6 +3124,7 @@
 	L2TP_PPP_ARGID_REMOTE_NAME,
 	L2TP_PPP_ARGID_PROXY_ARP,
 	L2TP_PPP_ARGID_OPTIONSFILE,
+	L2TP_PPP_ARGID_CLIENTIP_AS_IPPARAM,
 } l2tp_ppp_arg_ids_t;
 
 #undef ARG
@@ -3189,7 +3190,8 @@
 	ARG(USE_AS_DEFAULT_ROUTE, "default_route",	0,	bool,	"Use link as default route"),							\
 	ARG(MULTILINK,		"multilink",		0, 	bool, 	"Enable PPP multilink connections."),						\
 	ARG(PROXY_ARP,		"proxy_arp",		0, 	bool, 	"Use proxy arp."),								\
-	ARG(OPTIONSFILE,	"optionsfile",		0,	string, "ppp options file to use")
+	ARG(OPTIONSFILE,	"optionsfile",		0,	string, "ppp options file to use"),							\
+	ARG(CLIENTIP_AS_IPPARAM, "clientip_as_ipparam",	0,	bool,	"Pass the connecting client's IP as ipparam to pppd.")
 
 
 static struct cli_arg_entry l2tp_args_ppp_profile_create[] = {
@@ -3270,6 +3272,7 @@
 	FLG(MULTILINK,		"multilink",		"Enable PPP multilink connections."),						\
 	FLG(PROXY_ARP,		"proxy_arp",		"Use proxy arp."),
 	FLG(OPTIONSFILE,	"optionsfile",		"ppp options file to use"),
+	FLG(CLIENTIP_AS_IPPARAM, "clientip_as_ipparam",	"Pass the connecting client's IP as ipparam to pppd."),
 	{ NULL, },
 };
 
@@ -3500,6 +3503,9 @@
 		msg->optionsfile.valid = 1;
 		msg->flags2 |= L2TP_API_PPP_PROFILE_FLAG_OPTIONSFILE;
 		break;
+	case L2TP_PPP_ARGID_CLIENTIP_AS_IPPARAM:
+		L2TP_ACT_PARSE_ARG(arg, arg_value, msg->clientip_as_ipparam, msg->flags2, L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM);
+		break;
 	}
 
 	result = 0;
@@ -3871,6 +3877,9 @@
 		case L2TP_PPP_ARGID_OPTIONSFILE:
 			msg.flags2 |= L2TP_API_PPP_PROFILE_FLAG_OPTIONSFILE;
 			break;
+		case L2TP_PPP_ARGID_CLIENTIP_AS_IPPARAM:
+			msg.flags2 |= L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM;
+			break;
 		}
 	} L2TP_ACT_END();
 
@@ -4883,6 +4892,7 @@
  			    L2TP_API_PPP_PROFILE_FLAG_REMOTE_NAME |
  			    L2TP_API_PPP_PROFILE_FLAG_PROXY_ARP |
  			    L2TP_API_PPP_PROFILE_FLAG_OPTIONSFILE |
+ 			    L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM |
 			    L2TP_API_PPP_PROFILE_FLAG_AUTH_NONE |
 			    L2TP_API_PPP_PROFILE_FLAG_AUTH_REFUSE_EAP |
 			    L2TP_API_PPP_PROFILE_FLAG_AUTH_REFUSE_MSCHAPV2 |
@@ -5047,6 +5057,9 @@
 		if ((cfg->flags2 & L2TP_API_PPP_PROFILE_FLAG_OPTIONSFILE) && (OPTSTRING_PTR(cfg->optionsfile) != NULL)) {
 			fprintf(file, "\toptionsfile=%s \\\n", OPTSTRING_PTR(cfg->optionsfile));
 		}
+		if (cfg->flags2 & L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM) {
+			fprintf(file, "\tclientip_as_ipparam=%s \\\n", Y_OR_N(cfg->clientip_as_ipparam));
+		}
 		fprintf(file, "\n");
 	}
 }
diff -brau openl2tp-1.8.o/l2tp_config_parse.y openl2tp-1.8/l2tp_config_parse.y
--- openl2tp-1.8.o/l2tp_config_parse.y	2011-06-04 11:11:42.000000000 +0200
+++ openl2tp-1.8/l2tp_config_parse.y	2011-06-04 21:34:04.000000000 +0200
@@ -155,6 +155,7 @@
 %token BOOL
 %token IPADDRESS
 %token OPTIONSFILE
+%token CLIENTIP_AS_IPPARAM
 
 %token INITIAL_RCVD_LCP_CONFREQ
 %token CALLING_NUMBER
@@ -1180,6 +1181,11 @@
 			OPTSTRING(ppp_profile.optionsfile) = $3.buf;
 			ppp_profile.optionsfile.valid = 1;
 		}
+	|	CLIENTIP_AS_IPPARAM EQUALS BOOL
+		{
+			ppp_profile.flags2 |= L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM;
+			ppp_profile.clientip_as_ipparam = $3;
+		}
 	;
 
 tunnel_command
diff -brau openl2tp-1.8.o/l2tp_config_token.l openl2tp-1.8/l2tp_config_token.l
--- openl2tp-1.8.o/l2tp_config_token.l	2011-06-04 11:08:31.000000000 +0200
+++ openl2tp-1.8/l2tp_config_token.l	2011-06-04 21:34:50.000000000 +0200
@@ -192,6 +192,7 @@
 auth_none				{ return(AUTH_NOAUTH); }
 auth_peer				{ return(AUTH_PEER); }
 optionsfile				{ return(OPTIONSFILE); }
+clientip_as_ipparam			{ return(CLIENTIP_AS_IPPARAM); }
 
 {ws}		{ }
 {linecont}	{ lineno++; }
diff -brau openl2tp-1.8.o/l2tp_ppp.c openl2tp-1.8/l2tp_ppp.c
--- openl2tp-1.8.o/l2tp_ppp.c	2011-06-04 16:08:25.000000000 +0200
+++ openl2tp-1.8/l2tp_ppp.c	2011-06-04 21:42:37.000000000 +0200
@@ -71,6 +71,7 @@
 	int				auth_refuse_mschapv2:1;
 	int				auth_refuse_eap:1;
 	char				*optionsfile;
+	int				clientip_as_ipparam;
 };
 
 static struct l2tp_ppp_profile *l2tp_ppp_defaults;
@@ -245,6 +246,9 @@
 	if (msg->flags2 & L2TP_API_PPP_PROFILE_FLAG_OPTIONSFILE) {
 		L2TP_SET_OPTSTRING_VAR(profile, optionsfile);
 	}
+	if (msg->flags2 & L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM) {
+		profile->clientip_as_ipparam = msg->clientip_as_ipparam;
+	}
 
 out:
 	return result;
@@ -294,6 +298,7 @@
 	profile->chap_interval = l2tp_ppp_defaults->chap_interval;
 	profile->chap_max_challenge = l2tp_ppp_defaults->chap_max_challenge;
 	profile->chap_restart = l2tp_ppp_defaults->chap_restart;
+	profile->clientip_as_ipparam = l2tp_ppp_defaults->clientip_as_ipparam;
 	profile->pap_max_auth_requests = l2tp_ppp_defaults->pap_max_auth_requests;
 	profile->pap_restart_interval = l2tp_ppp_defaults->pap_restart_interval;
 	profile->pap_timeout = l2tp_ppp_defaults->pap_timeout;
@@ -553,6 +558,7 @@
 	result->chap_interval = profile->chap_interval;
 	result->chap_max_challenge = profile->chap_max_challenge;
 	result->chap_restart = profile->chap_restart;
+	result->clientip_as_ipparam = profile->clientip_as_ipparam;
 	result->pap_max_auth_requests = profile->pap_max_auth_requests;
 	result->pap_restart_interval = profile->pap_restart_interval;
 	result->pap_timeout = profile->pap_timeout;
@@ -893,6 +899,9 @@
 		}
 		profile->optionsfile = NULL;
 	}
+	if (msg.flags2 & L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM) {
+		profile->use_radius = L2TP_API_PPP_PROFILE_DEFAULT_CLIENTIP_AS_IPPARAM;
+	}
 
 	/* Clear all requested flags */
 	profile->flags &= ~(msg.flags);
diff -brau openl2tp-1.8.o/l2tp_rpc.x openl2tp-1.8/l2tp_rpc.x
--- openl2tp-1.8.o/l2tp_rpc.x	2011-06-04 11:06:08.000000000 +0200
+++ openl2tp-1.8/l2tp_rpc.x	2011-06-04 21:45:00.000000000 +0200
@@ -947,6 +947,7 @@
 const L2TP_API_PPP_PROFILE_FLAG_AUTH_REFUSE_PAP			= 131072;
 const L2TP_API_PPP_PROFILE_FLAG_AUTH_PEER			= 262144;
 const L2TP_API_PPP_PROFILE_FLAG_OPTIONSFILE			= 524288;
+const L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM		= 1048576;
 
 /* Default values for PPP profile attributes.
  * These are used if an explicit value is not provided by the user.
@@ -995,6 +996,7 @@
 const L2TP_API_PPP_PROFILE_DEFAULT_MULTILINK			= 0;
 const L2TP_API_PPP_PROFILE_DEFAULT_PROXY_ARP			= 0;
 const L2TP_API_PPP_PROFILE_DEFAULT_OPTIONSFILE			= "";
+const L2TP_API_PPP_PROFILE_DEFAULT_CLIENTIP_AS_IPPARAM		= 0;
 
 enum l2tp_api_ppp_sync_mode {
 	L2TP_API_PPP_SYNCMODE_SYNC_ASYNC,
@@ -1054,6 +1056,7 @@
 	optstring			remote_name;
 	bool				proxy_arp;
 	optstring			optionsfile;
+	bool				clientip_as_ipparam;
 };
 
 struct l2tp_api_ppp_profile_list_entry {
diff -brau openl2tp-1.8.o/plugins/ppp_unix.c openl2tp-1.8/plugins/ppp_unix.c
--- openl2tp-1.8.o/plugins/ppp_unix.c	2011-06-04 14:41:43.000000000 +0200
+++ openl2tp-1.8/plugins/ppp_unix.c	2011-06-04 22:11:54.000000000 +0200
@@ -295,6 +295,13 @@
 		argv[arg++] = "sync";
 	}
 
+	/* Check if we should pass ipparam */
+	if (params->flags2 & L2TP_API_PPP_PROFILE_FLAG_CLIENTIP_AS_IPPARAM) {
+		argv[arg++] = "ipparam";
+		ip.s_addr = l2tp_tunnel_get_peer_addr(ppp->tunnel)->sin_addr.s_addr;
+		argv[arg++] = strdup(inet_ntoa(ip));
+	}
+
 	/* ppp auth options */
 	if ((params->flags2 & L2TP_API_PPP_PROFILE_FLAG_AUTH_REFUSE_EAP) &&
 	     params->auth_refuse_eap) {