diff --git a/conf.c b/conf.c
index 943526d..cc08de3 100644
--- a/conf.c
+++ b/conf.c
@@ -630,8 +630,23 @@ static void conf_ip(struct ctx *c)
 		v4 = v6		= IP_VERSION_PROBE;
 	}
 
-	if (!c->ifi4 && !c->ifi6)
-		c->ifi4 = c->ifi6 = nl_get_ext_if(&v4, &v6);
+	if (v4 != IP_VERSION_DISABLED) {
+		if (!c->ifi4)
+			c->ifi4 = nl_get_ext_if(AF_INET);
+		if (!c->ifi4) {
+			warn("No external routable interface for IPv4");
+			v4 = IP_VERSION_DISABLED;
+		}
+	}
+
+	if (v6 != IP_VERSION_DISABLED) {
+		if (!c->ifi6)
+			c->ifi6 = nl_get_ext_if(AF_INET6);
+		if (!c->ifi6) {
+			warn("No external routable interface for IPv6");
+			v6 = IP_VERSION_DISABLED;
+		}
+	}
 
 	if (v4 != IP_VERSION_DISABLED) {
 		if (!c->gw4)
diff --git a/netlink.c b/netlink.c
index 66a95e4..8ad6a0c 100644
--- a/netlink.c
+++ b/netlink.c
@@ -126,13 +126,13 @@ static int nl_req(int ns, char *buf, const void *req, ssize_t len)
 }
 
 /**
- * nl_get_ext_if() - Get interface index supporting IP versions being probed
- * @v4:		Probe IPv4 support, set to ENABLED or DISABLED on return
- * @v6:		Probe IPv4 support, set to ENABLED or DISABLED on return
+ * nl_get_ext_if() - Get interface index supporting IP version being probed
+ * @af:	Address family (AF_INET or AF_INET6) to look for connectivity
+ *      for.
  *
  * Return: interface index, 0 if not found
  */
-unsigned int nl_get_ext_if(int *v4, int *v6)
+unsigned int nl_get_ext_if(sa_family_t af)
 {
 	struct { struct nlmsghdr nlh; struct rtmsg rtm; } req = {
 		.nlh.nlmsg_type	 = RTM_GETROUTE,
@@ -143,32 +143,14 @@ unsigned int nl_get_ext_if(int *v4, int *v6)
 		.rtm.rtm_table	 = RT_TABLE_MAIN,
 		.rtm.rtm_scope	 = RT_SCOPE_UNIVERSE,
 		.rtm.rtm_type	 = RTN_UNICAST,
+		.rtm.rtm_family	 = af,
 	};
-	unsigned int i, first_v4 = 0, first_v6 = 0;
-	uint8_t has_v4[PAGE_SIZE * 8 / 8] = { 0 }; /* See __dev_alloc_name() */
-	uint8_t has_v6[PAGE_SIZE * 8 / 8] = { 0 }; /* in kernel */
 	struct nlmsghdr *nh;
 	struct rtattr *rta;
 	struct rtmsg *rtm;
 	char buf[BUFSIZ];
-	long *word, tmp;
-	uint8_t *vmap;
 	ssize_t n;
 	size_t na;
-	int *v;
-
-	if (*v4 == IP_VERSION_PROBE) {
-		v = v4;
-		req.rtm.rtm_family = AF_INET;
-		vmap = has_v4;
-	} else if (*v6 == IP_VERSION_PROBE) {
-v6:
-		v = v6;
-		req.rtm.rtm_family = AF_INET6;
-		vmap = has_v6;
-	} else {
-		return 0;
-	}
 
 	if ((n = nl_req(0, buf, &req, sizeof(req))) < 0)
 		return 0;
@@ -178,7 +160,7 @@ v6:
 	for ( ; NLMSG_OK(nh, n); nh = NLMSG_NEXT(nh, n)) {
 		rtm = (struct rtmsg *)NLMSG_DATA(nh);
 
-		if (rtm->rtm_dst_len || rtm->rtm_family != req.rtm.rtm_family)
+		if (rtm->rtm_dst_len || rtm->rtm_family != af)
 			continue;
 
 		for (rta = RTM_RTA(rtm), na = RTM_PAYLOAD(nh); RTA_OK(rta, na);
@@ -190,57 +172,10 @@ v6:
 
 			ifi = *(unsigned int *)RTA_DATA(rta);
 
-			if (*v4 == IP_VERSION_DISABLED ||
-			    *v6 == IP_VERSION_DISABLED) {
-				*v = IP_VERSION_ENABLED;
-				return ifi;
-			}
-
-			if (v == v4 && !first_v4)
-				first_v4 = ifi;
-
-			if (v == v6 && !first_v6)
-				first_v6 = ifi;
-
-			bitmap_set(vmap, ifi);
+			return ifi;
 		}
 	}
 
-	if (v == v4 && *v6 == IP_VERSION_PROBE) {
-		req.nlh.nlmsg_seq = nl_seq++;
-		goto v6;
-	}
-
-	word = (long *)has_v4;
-	for (i = 0; i < ARRAY_SIZE(has_v4) / sizeof(long); i++, word++) {
-		tmp = *word;
-		while ((n = ffsl(tmp))) {
-			int ifi = i * sizeof(long) * 8 + n - 1;
-
-			if (!first_v4)
-				first_v4 = ifi;
-
-			tmp &= ~(1UL << (n - 1));
-			if (bitmap_isset(has_v6, ifi)) {
-				*v4 = *v6 = IP_VERSION_ENABLED;
-				return ifi;
-			}
-		}
-	}
-
-	if (first_v4) {
-		*v4 = IP_VERSION_ENABLED;
-		*v6 = IP_VERSION_DISABLED;
-		return first_v4;
-	}
-
-	if (first_v6) {
-		*v4 = IP_VERSION_DISABLED;
-		*v6 = IP_VERSION_ENABLED;
-		return first_v6;
-	}
-
-	err("No external routable interface for any IP protocol");
 	return 0;
 }
 
diff --git a/netlink.h b/netlink.h
index 261904e..5ce5037 100644
--- a/netlink.h
+++ b/netlink.h
@@ -7,7 +7,7 @@
 #define NETLINK_H
 
 int nl_sock_init(const struct ctx *c);
-unsigned int nl_get_ext_if(int *v4, int *v6);
+unsigned int nl_get_ext_if(sa_family_t af);
 void nl_route(int ns, unsigned int ifi, sa_family_t af, void *gw);
 void nl_addr(int ns, unsigned int ifi, sa_family_t af,
 	     void *addr, int *prefix_len, void *addr_l);
diff --git a/test/dhcp/passt b/test/dhcp/passt
index f45227a..11e0eb3 100644
--- a/test/dhcp/passt
+++ b/test/dhcp/passt
@@ -17,6 +17,7 @@ htools	ip jq sed tr head
 test	Interface name
 gout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 hout	HOST_IFNAME ip -j -4 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
+hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
 check	[ -n "__IFNAME__" ]
 
 test	DHCP: address
@@ -49,7 +50,7 @@ check	[ "__SEARCH__" = "__HOST_SEARCH__" ]
 test	DHCPv6: address
 guest	/sbin/dhclient -6 __IFNAME__
 gout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local'
-hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME__").addr_info[] | select(.scope == "global").local'
+hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local'
 check	[ "__ADDR6__" = "__HOST_ADDR6__" ]
 
 test	DHCPv6: route
diff --git a/test/dhcp/pasta b/test/dhcp/pasta
index 65b1d42..076ec8d 100644
--- a/test/dhcp/pasta
+++ b/test/dhcp/pasta
@@ -35,8 +35,9 @@ check	[ __MTU__ = 65520 ]
 
 test	DHCPv6: address
 ns	/sbin/dhclient -6 --no-pid __IFNAME__
+hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
 nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local'
-hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local'
+hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local'
 check	[ __ADDR6__ = __HOST_ADDR6__ ]
 
 test	DHCPv6: route
diff --git a/test/ndp/passt b/test/ndp/passt
index d6b4c40..8ef15e7 100644
--- a/test/ndp/passt
+++ b/test/ndp/passt
@@ -17,13 +17,13 @@ htools	ip jq sipcalc grep cut
 test	Interface name
 gout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 guest	ip link set dev __IFNAME__ up && sleep 2
-hout	HOST_IFNAME ip -j -4 route show|jq -rM '.[] | select(.dst == "default").dev'
+hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '.[] | select(.dst == "default").dev'
 check	[ -n "__IFNAME__" ]
 
 test	SLAAC: prefix
 gout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local'
 gout	PREFIX6 sipcalc __ADDR6__/64 | grep prefix | cut -d' ' -f4
-hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME__").addr_info[] | select(.scope == "global").local'
+hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local'
 hout	HOST_PREFIX6 sipcalc __HOST_ADDR6__/64 | grep prefix | cut -d' ' -f4
 check	[ "__PREFIX6__" = "__HOST_PREFIX6__" ]
 
diff --git a/test/two_guests/basic b/test/two_guests/basic
index f7c016d..e226178 100644
--- a/test/two_guests/basic
+++ b/test/two_guests/basic
@@ -19,6 +19,7 @@ test	Interface names
 g1out	IFNAME1 ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 g2out	IFNAME2 ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 hout	HOST_IFNAME ip -j -4 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
+hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
 check	[ -n "__IFNAME1__" ]
 check	[ -n "__IFNAME2__" ]
 
@@ -40,7 +41,7 @@ guest1	/sbin/dhclient -6 __IFNAME1__
 guest2	/sbin/dhclient -6 __IFNAME2__
 g1out	ADDR1_6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME1__").addr_info[] | select(.prefixlen == 128).local'
 g2out	ADDR2_6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME2__").addr_info[] | select(.prefixlen == 128).local'
-hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME__").addr_info[] | select(.scope == "global").local'
+hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local'
 check	[ "__ADDR1_6__" = "__HOST_ADDR6__" ]
 check	[ "__ADDR2_6__" = "__HOST_ADDR6__" ]