--- a/seq/aseqnet/aseqnet.c
+++ b/seq/aseqnet/aseqnet.c
@@ -29,6 +29,9 @@
 #include <assert.h>
 #include "aconfig.h"
 #include "gettext.h"
+#include <arpa/inet.h>
+#include <netinet/tcp.h>
+#include <sys/types.h>
 
 /*
  * prototypes
@@ -78,6 +81,8 @@
 static int verbose = 0;
 static int info = 0;
 
+static int ipv4only = 0;
+
 
 /*
  * main routine
@@ -90,6 +95,7 @@
 	{"help", 0, NULL, 'h'},
 	{"verbose", 0, NULL, 'v'},
 	{"info", 0, NULL, 'i'},
+	{"ipv4", 0, NULL, '4'},
 	{NULL, 0, NULL, 0},
 };
 
@@ -104,7 +110,7 @@
 	textdomain(PACKAGE);
 #endif
 
-	while ((c = getopt_long(argc, argv, "p:s:d:vi", long_option, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "p:s:d:vi4", long_option, NULL)) != -1) {
 		switch (c) {
 		case 'p':
 			if (isdigit(*optarg))
@@ -124,6 +130,9 @@
 		case 'i':
 			info++;
 			break;
+		case '4':
+			ipv4only++;
+			break;
 		default:
 			usage();
 			exit(1);
@@ -172,6 +181,7 @@
 	printf(_("  -d,--dest addr : write to given addr (client:port)\n"));
 	printf(_("  -v, --verbose : print verbose messages\n"));
 	printf(_("  -i, --info : print certain received events\n"));
+	printf(_("  -4, --ipv4 : IPv4 only\n"));
 }
 
 
@@ -329,25 +339,64 @@
 {
 	int i;
 	int curstate = 1;
-	struct sockaddr_in addr;
-
-	memset(&addr, 0, sizeof(addr));
-
-	addr.sin_family = AF_INET;
-	addr.sin_addr.s_addr = INADDR_ANY;
-	addr.sin_port = htons(port);
+	int ipv6only = 0;
+	int nodelay  = 1;
+	int quickack = 1;
+	struct sockaddr_in addr4;
+	struct sockaddr_in6 addr;
+
+	if (ipv4only == 0) {
+		memset(&addr, 0, sizeof(addr));
+
+		addr.sin6_family = AF_INET6;
+		inet_pton(AF_INET6, "::", &(addr.sin6_addr));
+		addr.sin6_port = htons(port);
+
+		sockfd = socket(PF_INET6, SOCK_STREAM, 0);
+		if (sockfd < 0)  {
+			perror("create socket");
+			exit(1);
+		}
+	} else {
+		memset(&addr4, 0, sizeof(addr4));
 
-	sockfd = socket(AF_INET, SOCK_STREAM, 0);
-	if (sockfd < 0)  {
-		perror("create socket");
-		exit(1);
+		addr4.sin_family = AF_INET;
+		addr4.sin_addr.s_addr = INADDR_ANY;
+		addr4.sin_port = htons(port);
+
+		sockfd = socket(AF_INET, SOCK_STREAM, 0);
+		if (sockfd < 0)  {
+			perror("create socket");
+			exit(1);
+		}
 	}
 	setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &curstate, sizeof(curstate));
 	/* the return value is ignored.. */
 
-	if (bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0)  {
-		perror("can't bind");
-		exit(1);
+	if (ipv4only == 0) {
+		/*    Force dual stack    */
+		setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, &ipv6only, sizeof(ipv6only));
+		/* the return value is ignored.. */
+	}
+
+	/*    Nagle and quickack  */
+	if ((setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, &nodelay, sizeof(nodelay))) < 0) {
+		perror("Error setsockopt tcp_nodelay");
+	}
+	if ((setsockopt(sockfd, IPPROTO_TCP, TCP_QUICKACK, &quickack, sizeof(quickack))) < 0) {
+		perror("Error setsockopt tcp_quickack");
+	}
+
+	if (ipv4only == 0) {
+		if (bind(sockfd, (struct sockaddr *) &addr, sizeof(addr)) < 0)  {
+			perror("can't bind");
+			exit(1);
+		}
+	} else {
+		if (bind(sockfd, (struct sockaddr *) &addr4, sizeof(addr4)) < 0)  {
+			perror("can't bind");
+			exit(1);
+		}
 	}
 
 	if (listen(sockfd, 5) < 0)  {
@@ -365,7 +414,8 @@
  */
 static void start_connection(void)
 {
-	struct sockaddr_in addr;
+	struct sockaddr_in6 addr;
+	struct sockaddr_in addr4;
 	int i;
 	socklen_t addr_len;
 
@@ -377,9 +427,15 @@
 		fprintf(stderr, _("too many connections!\n"));
 		exit(1);
 	}
-	memset(&addr, 0, sizeof(addr));
-	addr_len = sizeof(addr);
-	netfd[i] = accept(sockfd, (struct sockaddr *)&addr, &addr_len);
+	if (ipv4only == 0) {
+		memset(&addr, 0, sizeof(addr));
+		addr_len = sizeof(addr);
+		netfd[i] = accept(sockfd, (struct sockaddr *)&addr, &addr_len);
+	} else {
+		memset(&addr4, 0, sizeof(addr4));
+		addr_len = sizeof(addr4);
+		netfd[i] = accept(sockfd, (struct sockaddr *)&addr4, &addr_len);
+	}
 	if (netfd[i] < 0) {
 		perror("accept");
 		exit(1);
@@ -394,30 +450,57 @@
  */
 static void init_client(char *server, int port)
 {
-	struct sockaddr_in addr;
-	struct hostent *host;
+	struct addrinfo hints;
+	struct addrinfo *result, *rp;
 	int curstate = 1;
-	int fd;
+	int nodelay  = 1;
+	int quickack = 1;
+	int fd, s;
+	char portstr[8];
+	struct hostent *host;
 
-	if ((fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0){
-		perror("create socket");
+	memset(&hints, 0, sizeof(struct addrinfo));
+	if(ipv4only == 0)
+		hints.ai_family = AF_UNSPEC;
+	else
+		hints.ai_family = AF_INET;
+	hints.ai_socktype = SOCK_STREAM;
+	/* hints.ai_protocol = IPPROTO_TCP; */
+	hints.ai_flags    = 0;
+
+	memset(portstr, 0, 8);
+	snprintf(portstr, 6, "%d", port);
+
+	s = getaddrinfo(server, portstr, &hints, &result);
+	if (s != 0) {
+		fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
+		exit(1);
+	}
+	for (rp = result; rp != NULL; rp = rp->ai_next) {
+		fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+		if (fd == -1)
+			continue;
+		if (connect(fd, rp->ai_addr, rp->ai_addrlen) != -1)
+			break;
+		close(fd);
+	}
+	if (rp == NULL) {
+		fprintf(stderr, "Could not connect\n");
 		exit(1);
 	}
+
 	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &curstate, sizeof(curstate)) < 0) {
 		perror("setsockopt");
 		exit(1);
 	}
-	if ((host = gethostbyname(server)) == NULL){
-		fprintf(stderr, _("can't get address %s\n"), server);
-		exit(1);
+
+	if ((setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &nodelay, sizeof(nodelay))) < 0) {
+		perror("Error setsockopt tcp_nodelay");
 	}
-	addr.sin_port = htons(port);
-	addr.sin_family = AF_INET;
-	memcpy(&addr.sin_addr, host->h_addr, host->h_length);
-	if (connect(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
-		perror("connect");
-		exit(1);
+	if ((setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, &quickack, sizeof(quickack))) < 0) {
+		perror("Error setsockopt tcp_quickack");
 	}
+
 	if (verbose)
 		fprintf(stderr, _("ok.. connected\n"));
 	netfd[0] = fd;