diff --git a/contrib/tcpdump/addrtoname.c b/contrib/tcpdump/addrtoname.c
index af2a757325f0..8bfc3c379b49 100644
--- a/contrib/tcpdump/addrtoname.c
+++ b/contrib/tcpdump/addrtoname.c
@@ -467,15 +467,16 @@ isonsap_string(const u_char *nsap)
 	if (tp->e_name)
 		return tp->e_name;
 
-	tp->e_name = cp = (char *)malloc(nlen * 2 + 2);
+	tp->e_name = cp = (char *)malloc(nlen * 2 + 2 + (nlen>>1));
 	if (cp == NULL)
 		error("isonsap_string: malloc");
 
 	nsap++;
-	*cp++ = '/';
-	for (i = nlen; (int)--i >= 0;) {
+	for (i = 0; i < nlen; i++) {
 		*cp++ = hex[*nsap >> 4];
 		*cp++ = hex[*nsap++ & 0xf];
+		if (((i & 1) == 0) && (i + 1 < nlen))
+			*cp++ = '.';
 	}
 	*cp = '\0';
 	return (tp->e_name);
diff --git a/contrib/tcpdump/print-isoclns.c b/contrib/tcpdump/print-isoclns.c
index c7db005b780c..1825164b7e59 100644
--- a/contrib/tcpdump/print-isoclns.c
+++ b/contrib/tcpdump/print-isoclns.c
@@ -46,14 +46,16 @@ struct rtentry;
 #include "interface.h"
 #include "addrtoname.h"
 #include "ethertype.h"
+#include "extract.h"
 
-#define	CLNS	129
-#define	ESIS	130
-#define	ISIS	131
-#define	NULLNS	0
+#define	NLPID_CLNS	129	/* 0x81 */
+#define	NLPID_ESIS	130	/* 0x82 */
+#define	NLPID_ISIS	131	/* 0x83 */
+#define	NLPID_NULLNS	0
 
 static int osi_cksum(const u_char *, u_int, const u_char *, u_char *, u_char *);
 static void esis_print(const u_char *, u_int);
+static int isis_print(const u_char *, u_int);
 
 void
 isoclns_print(const u_char *p, u_int length, u_int caplen,
@@ -70,17 +72,17 @@ isoclns_print(const u_char *p, u_int length, u_int caplen,
 
 	switch (*p) {
 
-	case CLNS:
+	case NLPID_CLNS:
 		/* esis_print(&p, &length); */
-		printf("iso-clns");
+		printf("iso clns");
 		if (!eflag)
 			(void)printf(" %s > %s",
 				     etheraddr_string(esrc),
 				     etheraddr_string(edst));
 		break;
 
-	case ESIS:
-		printf("iso-esis");
+	case NLPID_ESIS:
+		printf("iso esis");
 		if (!eflag)
 			(void)printf(" %s > %s",
 				     etheraddr_string(esrc),
@@ -88,20 +90,20 @@ isoclns_print(const u_char *p, u_int length, u_int caplen,
 		esis_print(p, length);
 		return;
 
-	case ISIS:
-		printf("iso-isis");
+	case NLPID_ISIS:
+		printf("iso isis");
 		if (!eflag)
 			(void)printf(" %s > %s",
 				     etheraddr_string(esrc),
 				     etheraddr_string(edst));
-		/* isis_print(&p, &length); */
 		(void)printf(" len=%d ", length);
-		if (caplen > 1)
-			default_print_unaligned(p, caplen);
+		if (!isis_print(p, length)) {
+		    default_print_unaligned(p, caplen);
+		}
 		break;
 
-	case NULLNS:
-		printf("iso-nullns");
+	case NLPID_NULLNS:
+		printf("iso nullns");
 		if (!eflag)
 			(void)printf(" %s > %s",
 				     etheraddr_string(esrc),
@@ -109,7 +111,7 @@ isoclns_print(const u_char *p, u_int length, u_int caplen,
 		break;
 
 	default:
-		printf("iso-clns %02x", p[0]);
+		printf("iso clns %02x", p[0]);
 		if (!eflag)
 			(void)printf(" %s > %s",
 				     etheraddr_string(esrc),
@@ -206,7 +208,7 @@ esis_print(const u_char *p, u_int length)
 		dst = p; p += *p + 1;
 		if (p > snapend)
 			return;
-		printf(" %s", isonsap_string(dst));
+		printf("\n\t\t\t %s", isonsap_string(dst));
 		snpa = p; p += *p + 1;
 		is = p;   p += *p + 1;
 		if (p > snapend)
@@ -237,7 +239,7 @@ esis_print(const u_char *p, u_int length)
 		}
 		if (p > snapend)
 			return;
-		printf(" %s", isonsap_string(is));
+		printf("\n\t\t\t %s", isonsap_string(is));
 		li = ep - p;
 		break;
 	}
@@ -284,6 +286,257 @@ esis_print(const u_char *p, u_int length)
 		}
 }
 
+/*
+ * print_nsap
+ * Print out an NSAP. 
+ */
+
+void
+print_nsap (register const u_char *cp, register int length)
+{
+    int i;
+    
+    for (i = 0; i < length; i++) {
+	printf("%02x", *cp++);
+	if (((i & 1) == 0) && (i + 1 < length)) {
+	    printf(".");
+	}
+
+    }
+}
+
+/*
+ * IS-IS is defined in ISO 10589.  Look there for protocol definitions.
+ */
+
+#define SYSTEM_ID_LEN	sizeof(struct ether_addr)
+#define ISIS_VERSION	1
+#define PDU_TYPE_MASK	0x1F
+#define PRIORITY_MASK	0x7F
+
+#define L1_LAN_IIH	15
+#define L2_LAN_IIH	16
+#define PTP_IIH		17
+
+#define TLV_AREA_ADDR	1
+#define TLV_ISNEIGH	6
+#define TLV_PADDING	8
+#define TLV_AUTHENT	10
+
+struct isis_header {
+    u_char nlpid;
+    u_char fixed_len;
+    u_char version;			/* Protocol version? */
+    u_char id_length;
+    u_char enc_pdu_type;		/* 3 MSbs are reserved */
+    u_char pkt_version;			/* Packet format version? */
+    u_char reserved;
+    u_char enc_max_area;
+    u_char circuit;
+    u_char enc_source_id[SYSTEM_ID_LEN];
+    u_char enc_holding_time[2];
+    u_char enc_packet_len[2];
+    u_char enc_priority;
+    u_char enc_lan_id[SYSTEM_ID_LEN+1];
+};
+
+#define ISIS_HEADER_SIZE (15+(SYSTEM_ID_LEN<<1))
+
+/*
+ * isis_print
+ * Decode IS-IS packets.  Return 0 on error.
+ *
+ * So far, this is only smart enough to print IIH's.  Someday...
+ */
+
+static int
+isis_print (const u_char *p, u_int length)
+{
+    struct isis_header *header;
+    u_char pdu_type, max_area, priority, *pptr, type, len, *tptr, tmp, alen;
+    u_short packet_len, holding_time;
+
+    header = (struct isis_header *)p;
+    printf("\n\t\t\t");
+
+    /*
+     * Sanity checking of the header.
+     */
+    if (header->nlpid != NLPID_ISIS) {
+	printf(" coding error!");
+	return(0);
+    }
+
+    if (header->version != ISIS_VERSION) {
+	printf(" version %d packet not supported", header->version);
+	return(0);
+    }
+
+    if ((header->id_length != SYSTEM_ID_LEN) && (header->id_length != 0)) {
+	printf(" system ID length of %d is not supported",
+	       header->id_length);
+	return(0);
+    }
+
+    if ((header->fixed_len != ISIS_HEADER_SIZE)) {
+	printf(" bogus fixed header length %d should be %d",
+	       header->fixed_len, ISIS_HEADER_SIZE);
+	return(0);
+    }
+
+    pdu_type = header->enc_pdu_type & PDU_TYPE_MASK;
+    if ((pdu_type != L1_LAN_IIH) && (pdu_type != L2_LAN_IIH)) {
+	printf(" PDU type (%d) not supported", pdu_type);
+	return;
+    }
+    
+    if (header->pkt_version != ISIS_VERSION) {
+	printf(" version %d packet not supported", header->pkt_version);
+	return;
+    }
+
+    max_area = header->enc_max_area;
+    switch(max_area) {
+    case 0:
+	max_area = 3;			/* silly shit */
+	break;
+    case 255:
+	printf(" bad packet -- 255 areas");
+	return(0);
+    default:
+	break;
+    }
+
+    switch (header->circuit) {
+    case 0:
+	printf(" PDU with circuit type 0");
+	return(0);
+    case 1:
+	if (pdu_type == L2_LAN_IIH) {
+	    printf(" L2 IIH on an L1 only circuit");
+	    return(0);
+	}
+	break;
+    case 2:
+	if (pdu_type == L1_LAN_IIH) {
+	    printf(" L1 IIH on an L2 only circuit");
+	    return(0);
+	}
+	break;
+    case 3:
+	break;
+    default:
+	printf(" unknown circuit type");
+	return(0);
+    }
+	
+    holding_time = EXTRACT_16BITS(header->enc_holding_time);
+
+    packet_len = EXTRACT_16BITS(header->enc_packet_len);
+    if ((packet_len < ISIS_HEADER_SIZE) ||
+	(packet_len > length)) {
+	printf(" bogus packet length %d, real length %d", packet_len,
+	       length);
+	return(0);
+    }
+
+    priority = header->enc_priority & PRIORITY_MASK;
+
+    /*
+     * Now print the fixed header.
+     */
+    switch (pdu_type) {
+    case L1_LAN_IIH:
+	printf(" L1 lan iih, ");
+	break;
+    case L2_LAN_IIH:
+	printf(" L2 lan iih, ");
+	break;
+    }
+
+    printf("circuit ");
+    switch (header->circuit) {
+    case 1:
+	printf("l1 only, ");
+	break;
+    case 2:
+	printf("l2 only, ");
+	break;
+    case 3:
+	printf("l1-l2, ");
+	break;
+    }
+
+    printf ("holding time %d ", holding_time);
+    printf ("\n\t\t\t source %s, length %d",
+	    etheraddr_string(header->enc_source_id), packet_len);
+    printf ("\n\t\t\t lan id %s(%d)", etheraddr_string(header->enc_lan_id),
+	    header->enc_lan_id[SYSTEM_ID_LEN]);
+
+    /*
+     * Now print the TLV's.
+     */
+    packet_len -= ISIS_HEADER_SIZE;
+    pptr = (char *)p + ISIS_HEADER_SIZE;
+    while (packet_len >= 2) {
+	if (pptr >= snapend) {
+	    printf("\n\t\t\t packet exceeded snapshot");
+	    return(1);
+	}
+	type = *pptr++;
+	len = *pptr++;
+	packet_len -= 2;
+	if (len > packet_len) {
+	    break;
+	}
+
+	switch (type) {
+	case TLV_AREA_ADDR:
+	    printf("\n\t\t\t area addresses");
+	    tmp = len;
+	    tptr = pptr;
+	    alen = *tptr++;
+	    while (tmp && alen < tmp) {
+		printf("\n\t\t\t ");
+		print_nsap(tptr, alen);
+		printf(" (%d)", alen);
+		tptr += alen;
+		tmp -= alen + 1;
+		alen = *tptr++;
+	    }
+	    break;
+	case TLV_ISNEIGH:
+	    printf("\n\t\t\t neighbor addresses");
+	    tmp = len;
+	    tptr = pptr;
+	    while (tmp >= sizeof(struct ether_addr)) {
+		printf("\n\t\t\t %s", etheraddr_string(tptr));
+		tmp -= sizeof(struct ether_addr);
+		tptr += sizeof(struct ether_addr);
+	    }
+	    break;
+	case TLV_PADDING:
+	    printf("\n\t\t\t padding for %d bytes", len);
+	    break;
+	case TLV_AUTHENT:
+	    printf("\n\t\t\t authentication data");
+	    default_print(pptr, len);
+	    break;
+	default:
+	    printf("\n\t\t\t unknown TLV, type %d, length %d", type, len);
+	    break;
+	}
+
+	pptr += len;
+	packet_len -= len;
+    }
+
+    if (packet_len != 0) {
+	printf("\n\t\t\t %d straggler bytes", packet_len);
+    }
+    return(1);
+}
+
 static int
 osi_cksum(register const u_char *p, register u_int len,
 	  const u_char *toff, u_char *cksum, u_char *off)