diff --git a/lib/bind/include/resolv.h b/lib/bind/include/resolv.h
index 55556e461e..3771d12036 100644
--- a/lib/bind/include/resolv.h
+++ b/lib/bind/include/resolv.h
@@ -50,7 +50,7 @@
 
 /*
  *	@(#)resolv.h	8.1 (Berkeley) 6/2/93
- *	$Id: resolv.h,v 1.2 2001/04/02 07:53:19 marka Exp $
+ *	$Id: resolv.h,v 1.3 2001/05/21 14:31:29 marka Exp $
  */
 
 #ifndef _RESOLV_H_
@@ -218,6 +218,8 @@ typedef struct __res_state *res_state;
 #define	RES_NOCHECKNAME	0x00008000	/* do not check names for sanity. */
 #define	RES_KEEPTSIG	0x00010000	/* do not strip TSIG records */
 #define	RES_BLAST	0x00020000	/* blast all recursive servers */
+#define RES_NO_NIBBLE	0x00040000	/* disable IPv6 nibble mode reverse */
+#define RES_NO_BITSTRING 0x00080000	/* disable IPv6 bits tring mode reverse */
 /* KAME extensions: use higher bit to avoid conflict with ISC use */
 #define RES_USE_EDNS0	0x40000000	/* use EDNS0 if configured */
 #define RES_USE_A6	0x20000000	/* use A6 */
@@ -350,6 +352,7 @@ extern const struct res_sym __p_rcode_syms[];
 #define sym_ntos		__sym_ntos
 #define sym_ston		__sym_ston
 #define res_nopt		__res_nopt
+#define res_ndestroy		__res_ndestroy
 __BEGIN_DECLS
 int		res_hnok __P((const char *));
 int		res_ownok __P((const char *));
@@ -424,6 +427,9 @@ const char *	res_servicename __P((u_int16_t port, const char *proto));
 const char *	res_protocolname __P((int num));
 void		res_destroyprotolist __P((void));
 void		res_buildprotolist __P((void));
+const char *	res_get_nibblesuffix __P((res_state));
+const char *	res_get_bitstringsuffix __P((res_state));
+void		res_ndestroy __P((res_state));
 __END_DECLS
 
 #endif /* !_RESOLV_H_ */
diff --git a/lib/bind/irs/dns_ho.c b/lib/bind/irs/dns_ho.c
index fedbc0ed9d..7238aeeaff 100644
--- a/lib/bind/irs/dns_ho.c
+++ b/lib/bind/irs/dns_ho.c
@@ -52,7 +52,7 @@
 /* BIND Id: gethnamaddr.c,v 8.15 1996/05/22 04:56:30 vixie Exp $ */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static const char rcsid[] = "$Id: dns_ho.c,v 1.1 2001/03/29 06:31:42 marka Exp $";
+static const char rcsid[] = "$Id: dns_ho.c,v 1.2 2001/05/21 14:31:30 marka Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 /* Imports. */
@@ -388,17 +388,18 @@ ho_byaddr(struct irs_ho *this, const void *addr, int len, int af)
 		q.answer = q.qbuf.buf;
 		q.anslen = sizeof(q.qbuf);
 		q.next = &q2;
-#ifdef RES_USE_DNAME
-		if ((pvt->res->options & RES_USE_DNAME) == 0)
+		if ((pvt->res->options & RES_NO_BITSTRING) != 0)
 			q.action = RESTGT_IGNORE;
 		else
-#endif
 			q.action = RESTGT_DOALWAYS;
 		q2.qclass = C_IN;
 		q2.qtype = T_PTR;
 		q2.answer = q2.qbuf.buf;
 		q2.anslen = sizeof(q2.qbuf);
-		q2.action = RESTGT_AFTERFAILURE;
+		if ((pvt->res->options & RES_NO_NIBBLE) != 0)
+			q2.action = RESTGT_IGNORE;
+		else
+			q2.action = RESTGT_AFTERFAILURE;
 		break;
 	default:
 		errno = EAFNOSUPPORT;
@@ -425,15 +426,18 @@ ho_byaddr(struct irs_ho *this, const void *addr, int len, int af)
 			qp += SPRINTF((qp, "\\[x"));
 			for (n = 0; n < IN6ADDRSZ; n++)
 				qp += SPRINTF((qp, "%02x", uaddr[n]));
-			strcpy(qp, "/128].ip6.arpa");
+			SPRINTF((qp, "/128].%s",
+				 res_get_bitstringsuffix(pvt->res)));
 		}
-		qp = q2.qname;
-		for (n = IN6ADDRSZ - 1; n >= 0; n--) {
-			qp += SPRINTF((qp, "%x.%x.",
-				       uaddr[n] & 0xf,
-				       (uaddr[n] >> 4) & 0xf));
+		if (q2.action != RESTGT_IGNORE) {
+			qp = q2.qname;
+			for (n = IN6ADDRSZ - 1; n >= 0; n--) {
+				qp += SPRINTF((qp, "%x.%x.",
+					       uaddr[n] & 0xf,
+					       (uaddr[n] >> 4) & 0xf));
+			}
+			strcpy(qp, res_get_nibblesuffix(pvt->res));
 		}
-		strcpy(qp, "ip6.int");
 		break;
 	default:
 		abort();
@@ -1048,6 +1052,7 @@ gethostans(struct irs_ho *this,
 	int (*name_ok)(const char *);
 	const HEADER *hp;
 	const u_char *eom;
+	const u_char *eor;
 	const u_char *cp;
 	const char *tname;
 	const char *hname;
@@ -1155,11 +1160,12 @@ gethostans(struct irs_ho *this,
 			cp += n;
 			continue;
 		}
+		eor = cp + n;
 		if ((qtype == T_A || qtype == T_AAAA || qtype == ns_t_a6 ||
 		     qtype == T_ANY) && type == T_CNAME) {
 			if (ap >= &pvt->host_aliases[MAXALIASES-1])
 				continue;
-			n = dn_expand(ansbuf, eom, cp, tbuf, sizeof tbuf);
+			n = dn_expand(ansbuf, eor, cp, tbuf, sizeof tbuf);
 			if (n < 0 || !maybe_ok(pvt->res, tbuf, name_ok)) {
 				had_error++;
 				continue;
@@ -1188,11 +1194,11 @@ gethostans(struct irs_ho *this,
 
 			/*
 			 * just replace the query target; do not update the
-			 * aliase list. (Or should we?)
+			 * alias list. (Or should we?)
 			 */
 			t0 = (qtype == T_PTR) ? tname : hname;
 
-			n = dn_expand(ansbuf, eom, cp, tbuf, sizeof(tbuf));
+			n = dn_expand(ansbuf, eor, cp, tbuf, sizeof(tbuf));
 			if (n < 0 || !maybe_dnok(pvt->res, tbuf)) {
 				had_error++;
 				continue;
@@ -1231,7 +1237,7 @@ gethostans(struct irs_ho *this,
 			continue;
 		}
 		if (qtype == T_PTR && type == T_CNAME) {
-			n = dn_expand(ansbuf, eom, cp, tbuf, sizeof tbuf);
+			n = dn_expand(ansbuf, eor, cp, tbuf, sizeof tbuf);
 			if (n < 0 || !maybe_dnok(pvt->res, tbuf)) {
 				had_error++;
 				continue;
@@ -1283,7 +1289,7 @@ gethostans(struct irs_ho *this,
 				cp += n;
 				continue;
 			}
-			n = dn_expand(ansbuf, eom, cp, bp, buflen);
+			n = dn_expand(ansbuf, eor, cp, bp, buflen);
 			if (n < 0 || !maybe_hnok(pvt->res, bp) ||
 			    n >= MAXHOSTNAMELEN) {
 				had_error++;
diff --git a/lib/bind/resolv/res_init.c b/lib/bind/resolv/res_init.c
index 1b423d7666..262c086268 100644
--- a/lib/bind/resolv/res_init.c
+++ b/lib/bind/resolv/res_init.c
@@ -70,7 +70,7 @@
 
 #if defined(LIBC_SCCS) && !defined(lint)
 static const char sccsid[] = "@(#)res_init.c	8.1 (Berkeley) 6/7/93";
-static const char rcsid[] = "$Id: res_init.c,v 1.3 2001/04/06 05:35:41 marka Exp $";
+static const char rcsid[] = "$Id: res_init.c,v 1.4 2001/05/21 14:31:31 marka Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include "port_before.h"
@@ -189,6 +189,8 @@ __res_vinit(res_state statp, int preinit) {
 	    if (statp->_u._ext.ext != NULL) {
 	        memset(statp->_u._ext.ext, 0, sizeof(*statp->_u._ext.ext));
 		statp->_u._ext.ext->nsaddrs[0].sin = statp->nsaddr;
+		strcpy(statp->_u._ext.ext->nsuffix, "ip6.int");
+		strcpy(statp->_u._ext.ext->bsuffix, "ip6.arpa");
 	    }
 	}
 
@@ -438,6 +440,7 @@ res_setoptions(res_state statp, const char *options, const char *source)
 {
 	const char *cp = options;
 	int i;
+	struct __res_state_ext *ext = statp->_u._ext.ext;
 
 #ifdef DEBUG
 	if (statp->options & RES_DEBUG)
@@ -500,9 +503,40 @@ res_setoptions(res_state statp, const char *options, const char *source)
 		else if (!strncmp(cp, "dname", sizeof("dname") - 1)) {
 			statp->options |= RES_USE_DNAME;
 		}
+		else if (!strncmp(cp, "nibble:", sizeof("nibble:") - 1)) {
+			if (ext == NULL)
+				goto skip;
+			cp += sizeof("nibble:") - 1;
+			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix) - 1);
+			strncpy(ext->nsuffix, cp, i);
+			ext->nsuffix[i] = '\0';
+		}
+		else if (!strncmp(cp, "bitstring:", sizeof("bitstring:") - 1)) {
+			if (ext == NULL)
+				goto skip;
+			cp += sizeof("bitstring:") - 1;
+			i = MIN(strcspn(cp, " \t"), sizeof(ext->bsuffix) - 1);
+			strncpy(ext->bsuffix, cp, i);
+			ext->bsuffix[i] = '\0';
+		}
+		else if (!strncmp(cp, "v6revmode:", sizeof("v6revmode:") - 1)) {
+			cp += sizeof("v6revmode:") - 1;
+			if (!strncmp(cp, "nibble", sizeof("nibble") - 1)) {
+				statp->options &= ~RES_NO_NIBBLE;
+				statp->options |= RES_NO_BITSTRING;
+			} else if (!strncmp(cp, "bitstring",
+				    sizeof("bitstring") - 1)) {
+				statp->options |= RES_NO_NIBBLE;
+				statp->options &= ~RES_NO_BITSTRING;
+			} else if (!strncmp(cp, "both", sizeof("both") - 1)) {
+				statp->options &=
+					 ~(RES_NO_NIBBLE|RES_NO_BITSTRING);
+			}
+		}
 		else {
 			/* XXX - print a warning here? */
 		}
+   skip:
 		/* skip to next run of spaces */
 		while (*cp && *cp != ' ' && *cp != '\t')
 			cp++;
@@ -556,3 +590,26 @@ res_nclose(res_state statp) {
 		}
 	}
 }
+
+void
+res_ndestroy(res_state statp) {
+	res_nclose(statp);
+	if (statp->_u._ext.ext != NULL)
+		free(statp->_u._ext.ext);
+	statp->options &= ~RES_INIT;
+	statp->_u._ext.ext = NULL;
+}
+
+const char *
+res_get_nibblesuffix(res_state statp) {
+	if (statp->_u._ext.ext)
+		return (statp->_u._ext.ext->nsuffix);
+	return ("ip6.int");
+}
+
+const char *
+res_get_bitstringsuffix(res_state statp) {
+	if (statp->_u._ext.ext)
+		return (statp->_u._ext.ext->bsuffix);
+	return ("ip6.arpa");
+}
diff --git a/lib/bind/resolv/res_private.h b/lib/bind/resolv/res_private.h
index 12950cafc1..028c553557 100644
--- a/lib/bind/resolv/res_private.h
+++ b/lib/bind/resolv/res_private.h
@@ -17,6 +17,8 @@ struct __res_state_ext {
 			struct in6_addr in6a;
 		} addr, mask;
 	} sort_list[MAXRESOLVSORT];
+	char nsuffix[64];
+	char bsuffix[64];
 };
 
 extern int