Index: src/util.h
===================================================================
--- src/util.h	(revision 2535)
+++ src/util.h	(working copy)
@@ -42,6 +42,10 @@
 #define IFCONF_BUFFSIZE		16384
 #define IFCONF_BUFFMAXSIZE	1048576
 
+#ifndef GETHOSTNAME_DELAY
+#define GETHOSTNAME_DELAY	120
+#endif
+
 struct configfile {
 	char   *label;
 	off_t	seek;
@@ -106,6 +110,8 @@ extern int IfaceSetFlag(const char *ifname, int value)
 ssize_t GetDataAddrs(int sock, void *dbuf, size_t dbufsize,
 			  struct sockaddr_storage *peer, socklen_t peer_len,
 			  struct u_addr *addr);
+
+extern char* GetHostName(void);
 
 #ifndef	HAVE_NTOA_R
 extern char *ether_ntoa_r(const struct ether_addr *n, char *a);
Index: src/util.c
===================================================================
--- src/util.c	(revision 2535)
+++ src/util.c	(working copy)
@@ -25,6 +25,7 @@
 #include <netinet/if_ether.h>
 #include <net/ethernet.h>
 #include <osreldate.h>
+#include <time.h>
 
 /*
  * DEFINITIONS
@@ -1623,4 +1624,43 @@ int GetLocalSocket(void)
 	if (gLocalSocket < 0)
 	    gLocalSocket = socket(PF_LOCAL, socktype(SOCK_DGRAM), 0);
 	return(gLocalSocket);
+}
+
+/*
+ * Cache hostname and avoid frequent system calls
+ * but catch up with changes eventually.
+ */
+char* GetHostName(void)
+{
+	static const char *amnesiac = "NONAME";
+	static char	*hostname = NULL;
+	static long	 namelen;
+	static time_t	 was;
+	time_t		 now;
+
+	if (hostname == NULL) {
+		namelen = sysconf(_SC_HOST_NAME_MAX);
+		if (namelen <= 0)
+			namelen = MAXHOSTNAMELEN;
+		/* add space for terminating zero */
+		namelen++;
+		hostname = Malloc(MB_UTIL, namelen);
+		time(&was);
+
+		if (gethostname(hostname, namelen) < 0)
+			return (__DECONST(char*, amnesiac));
+		return (hostname);
+	}
+
+#if GETHOSTNAME_DELAY != 0
+	time(&now);
+	if (now - was < GETHOSTNAME_DELAY)
+		return (hostname);
+
+	was = now;
+#endif
+
+	if (gethostname(hostname, namelen) < 0)
+		return (__DECONST(char*, amnesiac));
+	return (hostname);
 }
Index: src/l2tp.c
===================================================================
--- src/l2tp.c	(revision 2533)
+++ src/l2tp.c	(working copy)
@@ -508,12 +508,8 @@ L2tpOpen(Link l)
 	/* Create vendor name AVP */
 	avps = ppp_l2tp_avp_list_create();
 
-	if (pi->conf.hostname[0] != 0) {
-	    strlcpy(hostname, pi->conf.hostname, sizeof(hostname));
-	} else {
-	    (void)gethostname(hostname, sizeof(hostname) - 1);
-	    hostname[sizeof(hostname) - 1] = '\0';
-	}
+	strlcpy(hostname, pi->conf.hostname[0] ? pi->conf.hostname :
+	    GetHostName(), sizeof(hostname));
 	cap = htonl(L2TP_BEARER_DIGITAL|L2TP_BEARER_ANALOG);
 	win = htons(8); /* XXX: this value is empirical. */
 	if ((ppp_l2tp_avp_list_append(avps, 1, 0, AVP_HOST_NAME,
@@ -1478,12 +1474,8 @@ L2tpServerEvent(int type, void *arg)
 	/* Create vendor name AVP */
 	avps = ppp_l2tp_avp_list_create();
 
-	if (pi->conf.hostname[0] != 0) {
-	    strlcpy(hostname, pi->conf.hostname, sizeof(hostname));
-	} else {
-	    (void)gethostname(hostname, sizeof(hostname) - 1);
-	    hostname[sizeof(hostname) - 1] = '\0';
-	}
+	strlcpy(hostname, pi->conf.hostname[0] ? pi->conf.hostname :
+	    GetHostName(), sizeof(hostname));
 	cap = htonl(L2TP_BEARER_DIGITAL|L2TP_BEARER_ANALOG);
 	win = htons(8); /* XXX: this value is empirical. */
 	if ((ppp_l2tp_avp_list_append(avps, 1, 0, AVP_HOST_NAME,
Index: src/l2tp_ctrl.c
===================================================================
--- src/l2tp_ctrl.c	(revision 2533)
+++ src/l2tp_ctrl.c	(working copy)
@@ -41,6 +41,7 @@
  */
 
 #include "ppp.h"
+#include "util.h"
 #include <netgraph.h>
 #include <netgraph/ng_message.h>
 #include <netgraph/ng_socket.h>
@@ -556,8 +557,7 @@ ppp_l2tp_ctrl_create(struct pevent_ctx *ctx, pthread_m
 	}
 	if ((index = ppp_l2tp_avp_list_find(ctrl->avps,
 	    0, AVP_HOST_NAME)) == -1) {
-		(void)gethostname(ctrl->self_name, sizeof(ctrl->self_name) - 1);
-		ctrl->self_name[sizeof(ctrl->self_name) - 1] = '\0';
+		strlcpy(ctrl->self_name, GetHostName(), sizeof(ctrl->self_name));
 		if (ppp_l2tp_avp_list_append(ctrl->avps, 1,
 		    0, AVP_HOST_NAME, ctrl->self_name, strlen(ctrl->self_name)) == -1)
 			goto fail;
Index: src/pppoe.c
===================================================================
--- src/pppoe.c	(revision 2534)
+++ src/pppoe.c	(working copy)
@@ -1435,17 +1435,8 @@ PppoeListenEvent(int type, void *arg)
 	/* Put the PPPoE node into OFFER mode. */
 	memset(idata, 0, sizeof(*idata));
 	strlcpy(idata->hook, session_hook, sizeof(idata->hook));
-	if (pi->acname[0] != 0) {
-		strlcpy(idata->data, pi->acname, MAX_SESSION);
-	} else {
-		if (gethostname(idata->data, MAX_SESSION) == -1) {
-			Log(LG_ERR, ("[%s] PPPoE: gethostname() failed",
-			    l->name));
-			idata->data[0] = 0;
-		}
-		if (idata->data[0] == 0)
-			strlcpy(idata->data, "NONAME", MAX_SESSION);
-	}
+	strlcpy(idata->data, pi->acname[0] ? pi->acname :
+	    GetHostName(), MAX_SESSION);
 	idata->data_len=strlen(idata->data);
 
 	if (NgSendMsg(pi->PIf->csock, path, NGM_PPPOE_COOKIE, NGM_PPPOE_OFFER,
Index: src/pptp_ctrl.c
===================================================================
--- src/pptp_ctrl.c	(revision 2533)
+++ src/pptp_ctrl.c	(working copy)
@@ -955,8 +955,7 @@ abort:
     msg.frameCap = PPTP_FRAMECAP_ANY;
     msg.bearCap = PPTP_BEARCAP_ANY;
     msg.firmware = PPTP_FIRMWARE_REV;
-    gethostname(c->self_name, sizeof(c->self_name) - 1);
-    c->self_name[sizeof(c->self_name) - 1] = '\0';
+    strlcpy(c->self_name, GetHostName(), sizeof(c->self_name));
     strlcpy(msg.host, c->self_name, sizeof(msg.host));
     strlcpy(msg.vendor, MPD_VENDOR, sizeof(msg.vendor));
     PptpCtrlNewCtrlState(c, PPTP_CTRL_ST_WAIT_CTL_REPLY);
@@ -2020,8 +2019,7 @@ PptpStartCtrlConnRequest(PptpCtrl c, struct pptpStartC
     reply.bearCap = PPTP_BEARCAP_ANY;
     reply.firmware = PPTP_FIRMWARE_REV;
     reply.result = PPTP_SCCR_RESL_OK;
-    gethostname(c->self_name, sizeof(c->self_name) - 1);
-    c->self_name[sizeof(c->self_name) - 1] = '\0';
+    strlcpy(c->self_name, GetHostName(), sizeof(c->self_name));
     strlcpy(reply.host, c->self_name, sizeof(reply.host));
     strlcpy(reply.vendor, MPD_VENDOR, sizeof(reply.vendor));
 
Index: src/radius.c
===================================================================
--- src/radius.c	(revision 2533)
+++ src/radius.c	(working copy)
@@ -563,7 +563,6 @@ static int
 RadiusStart(AuthData auth, short request_type)
 {
   RadConf 	const conf = &auth->conf.radius;  
-  char		host[MAXHOSTNAMELEN];
   int		porttype;
   char		buf[48];
   char		*tmpval;
@@ -577,17 +576,7 @@ RadiusStart(AuthData auth, short request_type)
     return (RAD_NACK);
   }
 
-    if (conf->identifier) {
-	tmpval = conf->identifier;
-    } else {
-	if (gethostname(host, sizeof(host)) == -1) {
-	    Log(LG_ERR|LG_RADIUS,
-		("[%s] RADIUS: gethostname() for RAD_NAS_IDENTIFIER failed",
-    		auth->info.lnkname));
-	    return (RAD_NACK);
-	}
-	tmpval = host;
-    }
+    tmpval = conf->identifier ? conf->identifier : GetHostName();
     Log(LG_RADIUS2, ("[%s] RADIUS: Put RAD_NAS_IDENTIFIER: %s", 
 	auth->info.lnkname, tmpval));
     if (rad_put_string(auth->radius.handle, RAD_NAS_IDENTIFIER, tmpval) == -1)  {