diff --git a/tpws/params.h b/tpws/params.h
index c6c8aeb..309cfca 100644
--- a/tpws/params.h
+++ b/tpws/params.h
@@ -74,6 +74,7 @@ struct params_s
 
 	struct sockaddr_in connect_bind4;
 	struct sockaddr_in6 connect_bind6;
+	char connect_bind6_ifname[IF_NAMESIZE];
 
 	int debug;
 
diff --git a/tpws/tpws.c b/tpws/tpws.c
index 2b1991f..14ea24f 100644
--- a/tpws/tpws.c
+++ b/tpws/tpws.c
@@ -797,7 +797,13 @@ void parse_params(int argc, char *argv[])
 				else if (inet_pton(AF_INET6, optarg, &params.connect_bind6.sin6_addr))
 				{
 					params.connect_bind6.sin6_family = AF_INET6;
-					if (p && *p) params.connect_bind6.sin6_scope_id=if_nametoindex(p);
+					if (p && *p)
+					{
+						// copy interface name for delayed resolution
+						strncpy(params.connect_bind6_ifname,p,sizeof(params.connect_bind6_ifname));
+						params.connect_bind6_ifname[sizeof(params.connect_bind6_ifname)-1]=0;
+					}
+
 				}
 				else
 				{
diff --git a/tpws/tpws_conn.c b/tpws/tpws_conn.c
index 70b05cf..1222c0a 100644
--- a/tpws/tpws_conn.c
+++ b/tpws/tpws_conn.c
@@ -403,6 +403,17 @@ static int connect_remote(const struct sockaddr *remote_addr, bool bApplyConnect
 	}
 	else if(remote_addr->sa_family == params.connect_bind6.sin6_family)
 	{
+		if (*params.connect_bind6_ifname && !params.connect_bind6.sin6_scope_id)
+		{
+			params.connect_bind6.sin6_scope_id=if_nametoindex(params.connect_bind6_ifname);
+			if (!params.connect_bind6.sin6_scope_id)
+			{
+				fprintf(stderr, "interface name not found : %s\n", params.connect_bind6_ifname);
+				close(remote_fd);
+				return -1;
+			}
+		}
+
 		if (bind(remote_fd, (struct sockaddr *)&params.connect_bind6, sizeof(struct sockaddr_in6)) == -1)
 		{
 			perror("bind on connect");