diff --git a/config.c b/config.c
index 50548eee..d3d76f57 100644
--- a/config.c
+++ b/config.c
@@ -1292,6 +1292,10 @@ void setup_config_box(struct controlbox *b, struct sesslist *sesslist,
 			  'n', HELPCTX(connection_nodelay),
 			  dlg_stdcheckbox_handler,
 			  I(offsetof(Config,tcp_nodelay)));
+	    ctrl_checkbox(s, "Enable TCP keepalives (SO_KEEPALIVE option)",
+			  'p', HELPCTX(connection_tcpkeepalive),
+			  dlg_stdcheckbox_handler,
+			  I(offsetof(Config,tcp_keepalives)));
 	}
 
     }
diff --git a/doc/config.but b/doc/config.but
index 7572a779..2279db58 100644
--- a/doc/config.but
+++ b/doc/config.but
@@ -1,4 +1,4 @@
-\versionid $Id: config.but,v 1.83 2004/06/15 11:31:30 jacob Exp $
+\versionid $Id: config.but,v 1.84 2004/06/20 17:07:36 jacob Exp $
 
 \C{config} Configuring PuTTY
 
@@ -1506,7 +1506,8 @@ what \e{kind} of network problems you have between you and the
 server.
 
 Keepalives are only supported in Telnet and SSH; the Rlogin and Raw
-protocols offer no way of implementing them.
+protocols offer no way of implementing them. (For an alternative, see
+\k{config-tcp-keepalives}.)
 
 Note that if you are using SSH1 and the server has a bug that makes
 it unable to deal with SSH1 ignore messages (see
@@ -1525,6 +1526,34 @@ types of server.
 
 The Nagle algorithm is disabled by default.
 
+\S{config-tcp-keepalives} \q{Enable TCP keepalives}
+
+\cfg{winhelp-topic}{connection.tcpkeepalive}
+
+\e{NOTE:} TCP keepalives should not be confused with the
+application-level keepalives described in \k{config-keepalive}. If in
+doubt, you probably want application-level keepalives; TCP keepalives
+are provided for completeness.
+
+The idea of TCP keepalives is similar to application-level keepalives,
+and the same caveats apply. The main differences are:
+
+\b TCP keepalives are available on \e{all} connection types, including
+Raw and Rlogin.
+
+\b The interval between TCP keepalives is usually much longer,
+typically two hours; this is set by the operating system, and cannot
+be configured within PuTTY.
+
+\b If the operating system does not receive a response to a keepalive,
+it may send out more in quick succession and if terminate the connection
+if no response is received.
+
+TCP keepalives may be useful for ensuring that half-open connections
+are terminated than for keeping a connection alive.
+
+TCP keepalives are disabled by default.
+
 \H{config-proxy} The Proxy panel
 
 \cfg{winhelp-topic}{proxy.main}
diff --git a/mac/macnet.c b/mac/macnet.c
index 106a6315..9fab15bc 100644
--- a/mac/macnet.c
+++ b/mac/macnet.c
@@ -12,7 +12,7 @@ struct macnet_stack {
     void (*addrcopy)(SockAddr, char *);
     void (*addr_free)(SockAddr);
     Socket (*skregister)(void *, Plug); /* "register" is a reserved word */
-    Socket (*new)(SockAddr, int, int, int, int, Plug);
+    Socket (*new)(SockAddr, int, int, int, int, int, Plug);
     Socket (*newlistener)(char *, int, Plug, int);
     char *(*addr_error)(SockAddr);
     void (*poll)(void);
@@ -128,11 +128,12 @@ Socket sk_register(void *sock, Plug plug)
 }
 
 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
-	      int nodelay, Plug plug)
+	      int nodelay, int keepalive, Plug plug)
 {
 
     if (stack != NULL)
-	return stack->new(addr, port, privport, oobinline, nodelay, plug);
+	return stack->new(addr, port, privport, oobinline, nodelay, keepalive,
+			  plug);
     return NULL;
 }
 
diff --git a/mac/macterm.c b/mac/macterm.c
index 88eb2668..7766c7b9 100644
--- a/mac/macterm.c
+++ b/mac/macterm.c
@@ -1,4 +1,4 @@
-/* $Id: macterm.c,v 1.75 2003/05/04 14:18:18 simon Exp $ */
+/* $Id: macterm.c,v 1.76 2004/06/20 17:07:37 jacob Exp $ */
 /*
  * Copyright (c) 1999 Simon Tatham
  * Copyright (c) 1999, 2002 Ben Harris
@@ -158,7 +158,8 @@ void mac_startsession(Session *s)
     term_provide_logctx(s->term, s->logctx);
 
     errmsg = s->back->init(s, &s->backhandle, &s->cfg, s->cfg.host,
-			   s->cfg.port, &s->realhost, s->cfg.tcp_nodelay);
+			   s->cfg.port, &s->realhost, s->cfg.tcp_nodelay,
+			   s->cfg.tcp_keepalives);
     if (errmsg != NULL)
 	fatalbox("%s", errmsg);
     s->back->provide_logctx(s->backhandle, s->logctx);
diff --git a/mac/mtcpnet.c b/mac/mtcpnet.c
index a8404b7a..791557d2 100644
--- a/mac/mtcpnet.c
+++ b/mac/mtcpnet.c
@@ -410,7 +410,7 @@ Socket mactcp_register(void *sock, Plug plug)
 static TCPNotifyUPP mactcp_asr_upp;
 
 Socket mactcp_new(SockAddr addr, int port, int privport, int oobinline,
-	      int nodelay, Plug plug)
+	      int nodelay, int keepalive, Plug plug)
 {
     static struct socket_function_table fn_table = {
 	mactcp_plug,
diff --git a/mac/otnet.c b/mac/otnet.c
index 7881e02a..35d3b16c 100644
--- a/mac/otnet.c
+++ b/mac/otnet.c
@@ -234,7 +234,7 @@ Socket ot_register(void *sock, Plug plug)
 }
 
 Socket ot_new(SockAddr addr, int port, int privport, int oobinline,
-	      int nodelay, Plug plug)
+	      int nodelay, int keepalive, Plug plug)
 {
     static struct socket_function_table fn_table = {
 	ot_tcp_plug,
@@ -281,7 +281,7 @@ Socket ot_new(SockAddr addr, int port, int privport, int oobinline,
 	return (Socket) ret;
     }
 
-    /* TODO: oobinline, nodelay */
+    /* TODO: oobinline, nodelay, keepalive */
 
     /*
      * Bind to local address.
diff --git a/network.h b/network.h
index cb077fdb..45742073 100644
--- a/network.h
+++ b/network.h
@@ -79,8 +79,8 @@ struct plug_function_table {
  * responsibility for freeing it */
 Socket new_connection(SockAddr addr, char *hostname,
 		      int port, int privport,
-		      int oobinline, int nodelay, Plug plug,
-		      const Config *cfg);
+		      int oobinline, int nodelay, int keepalive,
+		      Plug plug, const Config *cfg);
 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
 		    const Config *cfg);
 SockAddr name_lookup(char *host, int port, char **canonicalname,
@@ -90,8 +90,8 @@ SockAddr name_lookup(char *host, int port, char **canonicalname,
 /* (same caveat about addr as new_connection()) */
 Socket platform_new_connection(SockAddr addr, char *hostname,
 			       int port, int privport,
-			       int oobinline, int nodelay, Plug plug,
-			       const Config *cfg);
+			       int oobinline, int nodelay, int keepalive,
+			       Plug plug, const Config *cfg);
 
 /* socket functions */
 
@@ -111,7 +111,7 @@ void sk_addr_free(SockAddr addr);
 /* NB, control of 'addr' is passed via sk_new, which takes responsibility
  * for freeing it, as for new_connection() */
 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
-	      int nodelay, Plug p);
+	      int nodelay, int keepalive, Plug p);
 
 Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only);
 
diff --git a/plink.c b/plink.c
index a0a9541a..92769e86 100644
--- a/plink.c
+++ b/plink.c
@@ -564,7 +564,7 @@ int main(int argc, char **argv)
 	    (GetFileType(GetStdHandle(STD_INPUT_HANDLE)) == FILE_TYPE_CHAR);
 
 	error = back->init(NULL, &backhandle, &cfg, cfg.host, cfg.port,
-			   &realhost, nodelay);
+			   &realhost, nodelay, cfg.tcp_keepalives);
 	if (error) {
 	    fprintf(stderr, "Unable to open connection:\n%s", error);
 	    return 1;
diff --git a/portfwd.c b/portfwd.c
index d9941718..b95e5acd 100644
--- a/portfwd.c
+++ b/portfwd.c
@@ -390,7 +390,7 @@ const char *pfd_newconnect(Socket *s, char *hostname, int port,
     pr->dynamic = 0;
 
     pr->s = *s = new_connection(addr, dummy_realhost, port,
-				0, 1, 0, (Plug) pr, cfg);
+				0, 1, 0, 0, (Plug) pr, cfg);
     if ((err = sk_socket_error(*s)) != NULL) {
 	sfree(pr);
 	return err;
diff --git a/pproxy.c b/pproxy.c
index 5cb90162..9c4c2d89 100644
--- a/pproxy.c
+++ b/pproxy.c
@@ -10,8 +10,8 @@
 
 Socket platform_new_connection(SockAddr addr, char *hostname,
 			       int port, int privport,
-			       int oobinline, int nodelay, Plug plug,
-			       const Config *cfg)
+			       int oobinline, int nodelay, int keepalive,
+			       Plug plug, const Config *cfg)
 {
     return NULL;
 }
diff --git a/proxy.c b/proxy.c
index dd5c428c..d3bcca69 100644
--- a/proxy.c
+++ b/proxy.c
@@ -356,8 +356,8 @@ SockAddr name_lookup(char *host, int port, char **canonicalname,
 
 Socket new_connection(SockAddr addr, char *hostname,
 		      int port, int privport,
-		      int oobinline, int nodelay, Plug plug,
-		      const Config *cfg)
+		      int oobinline, int nodelay, int keepalive,
+		      Plug plug, const Config *cfg)
 {
     static const struct socket_function_table socket_fn_table = {
 	sk_proxy_plug,
@@ -388,7 +388,8 @@ Socket new_connection(SockAddr addr, char *hostname,
 	Socket sret;
 
 	if ((sret = platform_new_connection(addr, hostname, port, privport,
-					    oobinline, nodelay, plug, cfg)) !=
+					    oobinline, nodelay, keepalive,
+					    plug, cfg)) !=
 	    NULL)
 	    return sret;
 
@@ -444,7 +445,7 @@ Socket new_connection(SockAddr addr, char *hostname,
 	 */
 	ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port,
 				 privport, oobinline,
-				 nodelay, (Plug) pplug);
+				 nodelay, keepalive, (Plug) pplug);
 	if (sk_socket_error(ret->sub_socket) != NULL)
 	    return (Socket) ret;
 
@@ -456,7 +457,7 @@ Socket new_connection(SockAddr addr, char *hostname,
     }
 
     /* no proxy, so just return the direct socket */
-    return sk_new(addr, port, privport, oobinline, nodelay, plug);
+    return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
 }
 
 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
diff --git a/psftp.c b/psftp.c
index b134c503..10056bd5 100644
--- a/psftp.c
+++ b/psftp.c
@@ -1939,7 +1939,8 @@ static int psftp_connect(char *userhost, char *user, int portnumber)
 
     back = &ssh_backend;
 
-    err = back->init(NULL, &backhandle, &cfg, cfg.host, cfg.port, &realhost,0);
+    err = back->init(NULL, &backhandle, &cfg, cfg.host, cfg.port, &realhost,
+		     0, cfg.tcp_keepalives);
     if (err != NULL) {
 	fprintf(stderr, "ssh_init: %s\n", err);
 	return 1;
diff --git a/putty.h b/putty.h
index 723f1e6b..fed589bb 100644
--- a/putty.h
+++ b/putty.h
@@ -269,7 +269,8 @@ enum {
 struct backend_tag {
     const char *(*init) (void *frontend_handle, void **backend_handle,
 			 Config *cfg,
-			 char *host, int port, char **realhost, int nodelay);
+			 char *host, int port, char **realhost, int nodelay,
+			 int keepalive);
     void (*free) (void *handle);
     /* back->reconfig() passes in a replacement configuration. */
     void (*reconfig) (void *handle, Config *cfg);
@@ -329,6 +330,7 @@ struct config_tag {
     int warn_on_close;
     int ping_interval;		       /* in seconds */
     int tcp_nodelay;
+    int tcp_keepalives;
     /* Proxy options */
     char proxy_exclude_list[512];
     int proxy_dns;
diff --git a/raw.c b/raw.c
index 4c9e5bec..8c1f97fd 100644
--- a/raw.c
+++ b/raw.c
@@ -69,7 +69,8 @@ static void raw_sent(Plug plug, int bufsize)
  */
 static const char *raw_init(void *frontend_handle, void **backend_handle,
 			    Config *cfg,
-			    char *host, int port, char **realhost, int nodelay)
+			    char *host, int port, char **realhost, int nodelay,
+			    int keepalive)
 {
     static const struct plug_function_table fn_table = {
 	raw_closing,
@@ -115,7 +116,7 @@ static const char *raw_init(void *frontend_handle, void **backend_handle,
 	logevent(raw->frontend, buf);
 	sfree(buf);
     }
-    raw->s = new_connection(addr, *realhost, port, 0, 1, nodelay,
+    raw->s = new_connection(addr, *realhost, port, 0, 1, nodelay, keepalive,
 			    (Plug) raw, cfg);
     if ((err = sk_socket_error(raw->s)) != NULL)
 	return err;
diff --git a/rlogin.c b/rlogin.c
index af3bd876..f2b61d27 100644
--- a/rlogin.c
+++ b/rlogin.c
@@ -100,7 +100,7 @@ static void rlogin_sent(Plug plug, int bufsize)
 static const char *rlogin_init(void *frontend_handle, void **backend_handle,
 			       Config *cfg,
 			       char *host, int port, char **realhost,
-			       int nodelay)
+			       int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
 	rlogin_closing,
@@ -149,7 +149,7 @@ static const char *rlogin_init(void *frontend_handle, void **backend_handle,
 	sfree(buf);
     }
     rlogin->s = new_connection(addr, *realhost, port, 1, 0,
-			       nodelay, (Plug) rlogin, cfg);
+			       nodelay, keepalive, (Plug) rlogin, cfg);
     if ((err = sk_socket_error(rlogin->s)) != NULL)
 	return err;
 
diff --git a/scp.c b/scp.c
index 06bf0893..f7fa255f 100644
--- a/scp.c
+++ b/scp.c
@@ -450,7 +450,8 @@ static void do_cmd(char *host, char *user, char *cmd)
 
     back = &ssh_backend;
 
-    err = back->init(NULL, &backhandle, &cfg, cfg.host, cfg.port, &realhost,0);
+    err = back->init(NULL, &backhandle, &cfg, cfg.host, cfg.port, &realhost, 
+		     0, cfg.tcp_keepalives);
     if (err != NULL)
 	bump("ssh_init: %s", err);
     logctx = log_init(NULL, &cfg);
diff --git a/settings.c b/settings.c
index 99ec7eeb..a5f2e448 100644
--- a/settings.c
+++ b/settings.c
@@ -182,6 +182,7 @@ void save_open_settings(void *sesskey, int do_host, Config *cfg)
     write_setting_i(sesskey, "PingInterval", cfg->ping_interval / 60);	/* minutes */
     write_setting_i(sesskey, "PingIntervalSecs", cfg->ping_interval % 60);	/* seconds */
     write_setting_i(sesskey, "TCPNoDelay", cfg->tcp_nodelay);
+    write_setting_i(sesskey, "TCPKeepalives", cfg->tcp_keepalives);
     write_setting_s(sesskey, "TerminalType", cfg->termtype);
     write_setting_s(sesskey, "TerminalSpeed", cfg->termspeed);
 
@@ -411,6 +412,7 @@ void load_open_settings(void *sesskey, int do_host, Config *cfg)
 	cfg->ping_interval = pingmin * 60 + pingsec;
     }
     gppi(sesskey, "TCPNoDelay", 1, &cfg->tcp_nodelay);
+    gppi(sesskey, "TCPKeepalives", 0, &cfg->tcp_keepalives);
     gpps(sesskey, "TerminalType", "xterm", cfg->termtype,
 	 sizeof(cfg->termtype));
     gpps(sesskey, "TerminalSpeed", "38400,38400", cfg->termspeed,
diff --git a/ssh.c b/ssh.c
index dec48ce8..6c94ba49 100644
--- a/ssh.c
+++ b/ssh.c
@@ -2128,7 +2128,7 @@ static void ssh_sent(Plug plug, int bufsize)
  * freed by the caller.
  */
 static const char *connect_to_host(Ssh ssh, char *host, int port,
-				   char **realhost, int nodelay)
+				   char **realhost, int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
 	ssh_closing,
@@ -2169,7 +2169,7 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
     }
     ssh->fn = &fn_table;
     ssh->s = new_connection(addr, *realhost, port,
-			    0, 1, nodelay, (Plug) ssh, &ssh->cfg);
+			    0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg);
     if ((err = sk_socket_error(ssh->s)) != NULL) {
 	ssh->s = NULL;
 	return err;
@@ -6183,7 +6183,8 @@ static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
  */
 static const char *ssh_init(void *frontend_handle, void **backend_handle,
 			    Config *cfg,
-			    char *host, int port, char **realhost, int nodelay)
+			    char *host, int port, char **realhost, int nodelay,
+			    int keepalive)
 {
     const char *p;
     Ssh ssh;
@@ -6267,7 +6268,7 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
 
     ssh->protocol = NULL;
 
-    p = connect_to_host(ssh, host, port, realhost, nodelay);
+    p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
     if (p != NULL)
 	return p;
 
diff --git a/telnet.c b/telnet.c
index 2edae219..6f4f54ca 100644
--- a/telnet.c
+++ b/telnet.c
@@ -674,7 +674,7 @@ static void telnet_sent(Plug plug, int bufsize)
 static const char *telnet_init(void *frontend_handle, void **backend_handle,
 			       Config *cfg,
 			       char *host, int port, char **realhost,
-			       int nodelay)
+			       int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
 	telnet_closing,
@@ -729,7 +729,7 @@ static const char *telnet_init(void *frontend_handle, void **backend_handle,
 	sfree(buf);
     }
     telnet->s = new_connection(addr, *realhost, port, 0, 1,
-			       nodelay, (Plug) telnet, &telnet->cfg);
+			       nodelay, keepalive, (Plug) telnet, &telnet->cfg);
     if ((err = sk_socket_error(telnet->s)) != NULL)
 	return err;
 
diff --git a/testback.c b/testback.c
index 22860f33..bc2eb31f 100644
--- a/testback.c
+++ b/testback.c
@@ -1,4 +1,4 @@
-/* $Id: testback.c,v 1.9 2003/05/10 11:57:55 ben Exp $ */
+/* $Id: testback.c,v 1.10 2004/06/20 17:07:32 jacob Exp $ */
 /*
  * Copyright (c) 1999 Simon Tatham
  * Copyright (c) 1999 Ben Harris
@@ -34,9 +34,9 @@
 #include "putty.h"
 
 static const char *null_init(void *, void **, Config *, char *, int, char **,
-			     int);
+			     int, int);
 static const char *loop_init(void *, void **, Config *, char *, int, char **,
-			     int);
+			     int, int);
 static void null_free(void *);
 static void loop_free(void *);
 static void null_reconfig(void *, Config *);
@@ -72,14 +72,14 @@ struct loop_state {
 
 static const char *null_init(void *frontend_handle, void **backend_handle,
 			     Config *cfg, char *host, int port,
-			     char **realhost, int nodelay) {
+			     char **realhost, int nodelay, int keepalive) {
 
     return NULL;
 }
 
 static const char *loop_init(void *frontend_handle, void **backend_handle,
 			     Config *cfg, char *host, int port,
-			     char **realhost, int nodelay) {
+			     char **realhost, int nodelay, int keepalive) {
     struct loop_state *st = snew(struct loop_state);
 
     st->term = frontend_handle;
diff --git a/unix/pterm.c b/unix/pterm.c
index 87339fb4..8e2554d8 100644
--- a/unix/pterm.c
+++ b/unix/pterm.c
@@ -3367,7 +3367,8 @@ int pt_main(int argc, char **argv)
 
 	error = inst->back->init((void *)inst, &inst->backhandle,
                                  &inst->cfg, inst->cfg.host, inst->cfg.port,
-                                 &realhost, inst->cfg.tcp_nodelay);
+                                 &realhost, inst->cfg.tcp_nodelay,
+				 inst->cfg.tcp_keepalives);
 
 	if (error) {
 	    char *msg = dupprintf("Unable to open connection to %s:\n%s",
diff --git a/unix/pty.c b/unix/pty.c
index 7f46f1aa..20ddc801 100644
--- a/unix/pty.c
+++ b/unix/pty.c
@@ -486,7 +486,8 @@ static void pty_uxsel_setup(void)
  * freed by the caller.
  */
 static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
-			    char *host, int port, char **realhost, int nodelay)
+			    char *host, int port, char **realhost, int nodelay,
+			    int keepalive)
 {
     int slavefd;
     pid_t pid, pgrp;
diff --git a/unix/uxnet.c b/unix/uxnet.c
index 1e7d51b7..08fb4e17 100644
--- a/unix/uxnet.c
+++ b/unix/uxnet.c
@@ -378,7 +378,7 @@ Socket sk_register(OSSocket sockfd, Plug plug)
 }
 
 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
-	      int nodelay, Plug plug)
+	      int nodelay, int keepalive, Plug plug)
 {
     int s;
 #ifdef IPV6
@@ -433,6 +433,11 @@ Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
 	setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (void *) &b, sizeof(b));
     }
 
+    if (keepalive) {
+	int b = TRUE;
+	setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, (void *) &b, sizeof(b));
+    }
+
     /*
      * Bind to local address.
      */
diff --git a/unix/uxplink.c b/unix/uxplink.c
index e59a701b..6bf2c858 100644
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -557,7 +557,7 @@ int main(int argc, char **argv)
 	int nodelay = cfg.tcp_nodelay && isatty(0);
 
 	error = back->init(NULL, &backhandle, &cfg, cfg.host, cfg.port,
-			   &realhost, nodelay);
+			   &realhost, nodelay, cfg.tcp_keepalives);
 	if (error) {
 	    fprintf(stderr, "Unable to open connection:\n%s\n", error);
 	    return 1;
diff --git a/unix/uxproxy.c b/unix/uxproxy.c
index b3f75e81..1191a61a 100644
--- a/unix/uxproxy.c
+++ b/unix/uxproxy.c
@@ -221,8 +221,8 @@ static int localproxy_select_result(int fd, int event)
 
 Socket platform_new_connection(SockAddr addr, char *hostname,
 			       int port, int privport,
-			       int oobinline, int nodelay, Plug plug,
-			       const Config *cfg)
+			       int oobinline, int nodelay, int keepalive,
+			       Plug plug, const Config *cfg)
 {
     char *cmd;
 
diff --git a/window.c b/window.c
index 71f30b4d..e720ed3c 100644
--- a/window.c
+++ b/window.c
@@ -611,7 +611,8 @@ int WINAPI WinMain(HINSTANCE inst, HINSTANCE prev, LPSTR cmdline, int show)
 	char *realhost;
 
 	error = back->init(NULL, &backhandle, &cfg,
-			   cfg.host, cfg.port, &realhost, cfg.tcp_nodelay);
+			   cfg.host, cfg.port, &realhost, cfg.tcp_nodelay,
+			   cfg.tcp_keepalives);
 	back->provide_logctx(backhandle, logctx);
 	if (error) {
 	    char *str = dupprintf("%s Error", appname);
diff --git a/winhelp.h b/winhelp.h
index bbde922b..5271f924 100644
--- a/winhelp.h
+++ b/winhelp.h
@@ -63,6 +63,7 @@
 #define WINHELP_CTX_connection_username "connection.username"
 #define WINHELP_CTX_connection_keepalive "connection.keepalive"
 #define WINHELP_CTX_connection_nodelay "connection.nodelay"
+#define WINHELP_CTX_connection_tcpkeepalive "connection.tcpkeepalive"
 #define WINHELP_CTX_proxy_type "proxy.type"
 #define WINHELP_CTX_proxy_main "proxy.main"
 #define WINHELP_CTX_proxy_exclude "proxy.exclude"
diff --git a/winnet.c b/winnet.c
index 21a2f293..bcb22bf4 100644
--- a/winnet.c
+++ b/winnet.c
@@ -658,7 +658,7 @@ Socket sk_register(void *sock, Plug plug)
 }
 
 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
-	      int nodelay, Plug plug)
+	      int nodelay, int keepalive, Plug plug)
 {
     static const struct socket_function_table fn_table = {
 	sk_tcp_plug,
@@ -722,6 +722,11 @@ Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
 	p_setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (void *) &b, sizeof(b));
     }
 
+    if (keepalive) {
+	BOOL b = TRUE;
+	p_setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, (void *) &b, sizeof(b));
+    }
+
     /*
      * Bind to local address.
      */
diff --git a/x11fwd.c b/x11fwd.c
index 049381b4..b0b82698 100644
--- a/x11fwd.c
+++ b/x11fwd.c
@@ -310,7 +310,7 @@ const char *x11_init(Socket * s, char *display, void *c, void *auth,
     pr->c = c;
 
     pr->s = *s = new_connection(addr, dummy_realhost, port,
-				0, 1, 0, (Plug) pr, cfg);
+				0, 1, 0, 0, (Plug) pr, cfg);
     if ((err = sk_socket_error(*s)) != NULL) {
 	sfree(pr);
 	return err;