--- src/libradius/radius_socket.c.orig	2023-03-28 04:00:49.000000000 +0700
+++ src/libradius/radius_socket.c	2023-11-07 14:02:24.056213000 +0700
@@ -130,6 +130,15 @@ struct private_radius_socket_t {
 static bool check_connection(private_radius_socket_t *this,
 							 int *fd, uint16_t port)
 {
+	union {
+		struct sockaddr sockaddr;
+		struct sockaddr_in sin;
+		struct sockaddr_in6 sin6;
+	} addr;
+	socklen_t addrlen;
+	char	*s;
+	int	family;
+
 	if (*fd == -1)
 	{
 		host_t *server;
@@ -141,13 +150,29 @@ static bool check_connection(private_radius_socket_t *
 				 this->address);
 			return FALSE;
 		}
-		*fd = socket(server->get_family(server), SOCK_DGRAM, IPPROTO_UDP);
+
+		family = server->get_family(server);
+		*fd = socket(family, SOCK_DGRAM, IPPROTO_UDP);
 		if (*fd == -1)
 		{
 			DBG1(DBG_CFG, "opening RADIUS socket for %#H failed: %s",
 				 server, strerror(errno));
 			server->destroy(server);
 			return FALSE;
+		}
+
+		switch (family)
+		{
+			case AF_INET:
+			  memset(&addr, 0, sizeof(addr));
+			  addr.sockaddr.sa_family = family;
+			  addrlen = sizeof(addr.sin);
+			  s = getenv("STRONGSWAN_RADCLIENT_BIND");
+			  if (s && inet_pton(family, s, &addr.sin.sin_addr))
+			    if (bind(*fd, &addr.sockaddr, addrlen) < 0)
+			      DBG1(DBG_NET,
+			      	"unable to bind RADIUS socket to %s: %s",
+			      	s, strerror(errno));
 		}
 		if (connect(*fd, server->get_sockaddr(server),
 					*server->get_sockaddr_len(server)) < 0)