diff --git a/main.go b/main.go
index a05382c8..4f739cec 100644
--- a/main.go
+++ b/main.go
@@ -38,7 +38,7 @@ func handleMDNS(w dns.ResponseWriter, r *dns.Msg) {
 		q := r.Question[0]
 		ip, err := zone.MatchLocal(q.Name)
 		if err == nil {
-			m := makeDNSReply(r, q.Name, net.ParseIP(ip))
+			m := makeDNSReply(r, q.Name, ip)
 			mdnsClient.SendResponse(m)
 		} else if mdnsClient.IsInflightQuery(r) {
 			// ignore this - it's our own query received via multicast
@@ -53,7 +53,7 @@ func handleLocal(w dns.ResponseWriter, r *dns.Msg) {
 	q := r.Question[0]
 	ip, err := zone.MatchLocal(q.Name)
 	if err == nil {
-		m := makeDNSReply(r, q.Name, net.ParseIP(ip))
+		m := makeDNSReply(r, q.Name, ip)
 		w.WriteMsg(m)
 	} else {
 		log.Printf("Failed lookup for %s; sending mDNS query", q.Name)
diff --git a/server/http.go b/server/http.go
index aaa49e0b..4981aaad 100644
--- a/server/http.go
+++ b/server/http.go
@@ -3,6 +3,7 @@ package weavedns
 import (
 	"fmt"
 	"log"
+	"net"
 	"net/http"
 )
 
@@ -14,12 +15,20 @@ func ListenHttp(db Zone) {
 	http.HandleFunc("/add", func(w http.ResponseWriter, r *http.Request) {
 		name := r.FormValue("name")
 		addr := r.FormValue("ip")
-		weave_ip := r.FormValue("weave_ip")
-		if name != "" && addr != "" && weave_ip != "" {
-			log.Printf("Adding %s, %s, %s", name, addr, weave_ip)
-			db.AddRecord(name, addr, weave_ip)
+		weave_cidr := r.FormValue("weave_cidr")
+		if name != "" && addr != "" && weave_cidr != "" {
+			ip := net.ParseIP(addr)
+			weave_ip, subnet, err := net.ParseCIDR(weave_cidr)
+			if err == nil && ip != nil {
+				log.Printf("Adding %s (%s) -> %s", name, addr, weave_cidr)
+				db.AddRecord(name, ip, weave_ip, subnet)
+			} else if err != nil {
+				log.Printf("Invalid CIDR in request: %s", weave_cidr)
+			} else {
+				log.Printf("Invalid IP in request: %s", addr)
+			}
 		} else {
-			log.Printf("Invalid request: %s, %s, %s", name, addr, weave_ip)
+			log.Printf("Invalid request: %s, %s, %s", name, addr, weave_cidr)
 		}
 	})
 	address := fmt.Sprintf(":%d", UPDATE_PORT)
diff --git a/server/zone.go b/server/zone.go
index 1336adb1..824dd8d8 100644
--- a/server/zone.go
+++ b/server/zone.go
@@ -3,19 +3,20 @@ package weavedns
 import (
 	"github.com/miekg/dns"
 	"log"
+	"net"
 	"sync"
 )
 
 type Zone interface {
-	AddRecord(name string, ip string, weave_ip string) error
-	MatchLocal(name string) (string, error)
-	MatchGlobal(name string) (string, error)
+	AddRecord(string, net.IP, net.IP, *net.IPNet) error
+	MatchLocal(string) (net.IP, error)
 }
 
 type Record struct {
 	Name    string
-	Ip      string
-	WeaveIp string
+	Ip      net.IP
+	WeaveIp net.IP
+	Subnet  *net.IPNet
 }
 
 type ZoneDb struct {
@@ -30,31 +31,25 @@ func (ops LookupError) Error() string {
 }
 
 // Stop gap.
-func (zone *ZoneDb) match(name string) (string, error) {
+func (zone *ZoneDb) match(name string) (net.IP, error) {
 	for _, r := range zone.recs {
 		log.Printf("%s == %s ?", r.Name, name)
 		if r.Name == name {
 			return r.WeaveIp, nil
 		}
 	}
-	return "", LookupError(name)
+	return nil, LookupError(name)
 }
 
-func (zone *ZoneDb) MatchLocal(name string) (string, error) {
+func (zone *ZoneDb) MatchLocal(name string) (net.IP, error) {
 	zone.mx.Lock()
 	defer zone.mx.Unlock()
 	return zone.match(name)
 }
 
-func (zone *ZoneDb) MatchGlobal(name string) (string, error) {
+func (zone *ZoneDb) AddRecord(name string, ip net.IP, weave_ip net.IP, weave_subnet *net.IPNet) error {
 	zone.mx.Lock()
 	defer zone.mx.Unlock()
-	return zone.match(name)
-}
-
-func (zone *ZoneDb) AddRecord(name string, ip string, weave_ip string) error {
-	zone.mx.Lock()
-	defer zone.mx.Unlock()
-	zone.recs = append(zone.recs, Record{dns.Fqdn(name), ip, weave_ip})
+	zone.recs = append(zone.recs, Record{dns.Fqdn(name), ip, weave_ip, weave_subnet})
 	return nil
 }