diff --git a/service/userconfig.go b/service/userconfig.go
index dfb9968..2c9464b 100644
--- a/service/userconfig.go
+++ b/service/userconfig.go
@@ -2,8 +2,10 @@ package service
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"log"
+	"net"
 	"os"
 	"path"
 
@@ -18,7 +20,7 @@ func (uae UnauthorizedError) Error() string {
 }
 
 type UserConfig struct {
-	DB *viper.Viper
+	db *viper.Viper
 
 	UserName string
 	PassWord string
@@ -62,16 +64,22 @@ func LoadConfigForUser(username string, password string) (*UserConfig, error) {
 		return nil, fmt.Errorf("failed to parse config file %s: %v", configFile, err)
 	}
 
-	result := &UserConfig{DB: v}
+	result := &UserConfig{db: v, UserName: username}
+
+	err = result.db.Unmarshal(result)
+	if err != nil {
+		return nil, fmt.Errorf("failed to unmarshal config file %s: %v", configFile, err)
+	}
 
 	err = result.PasswordCheck(password)
 	if err != nil {
+		log.Printf("Failed to check password")
 		return nil, UnauthorizedError("pwcheck failed")
 	}
 
-	err = result.DB.Unmarshal(result)
+	err = result.Validate()
 	if err != nil {
-		return nil, fmt.Errorf("failed to unmarshal config file %s: %v", configFile, err)
+		return nil, fmt.Errorf("failed to parse config: %v", err)
 	}
 
 	return result, nil
@@ -85,8 +93,8 @@ func HashPassword(pw []byte) (string, error) {
 	return string(hash), nil
 }
 
-func (ur *UserConfig) PasswordCheck(pwToCheck string) error {
-	hashedPassword := []byte(ur.DB.GetString("password"))
+func (uc *UserConfig) PasswordCheck(pwToCheck string) error {
+	hashedPassword := []byte(uc.PassWord)
 	bytePwToCheck := []byte(pwToCheck)
 
 	err := bcrypt.CompareHashAndPassword(hashedPassword, bytePwToCheck)
@@ -94,6 +102,67 @@ func (ur *UserConfig) PasswordCheck(pwToCheck string) error {
 	return err
 }
 
+func (uco *UserConfigOther) ConvertIIDToAddress(localNet *net.IPNet) net.IP {
+	if localNet == nil {
+		return nil
+	}
+	out := make(net.IP, net.IPv6len)
+	ipiid := net.ParseIP(uco.V6IID)
+	for i := 0; i < net.IPv6len; i++ {
+		// We take the corresponding byte from the IID and mask it out with the
+		// inversed Mask of the network we got (in essence a Host Mask). This
+		// leaves us those bits, that are not taken by the netmask, so that we
+		// can OR all this together.
+		maskedIID := ipiid[i] &^ localNet.Mask[i]
+		out[i] = localNet.IP[i] | maskedIID
+	}
+	return out
+}
+
+func (ucn *UserConfigNFT) ValidateSetNames() bool {
+	if ucn.Set4 == "" && ucn.Set6 == "" {
+		return true
+	}
+	return ucn.Set4 != ucn.Set6
+}
+
+func (uc *UserConfig) Validate() error {
+	if !uc.Router.NFT.ValidateSetNames() {
+		return errors.New("router NFT set names invalid (probably identical for v4 and v6)")
+	}
+	if uc.Router.DNS == "" {
+		return errors.New("router record has no DNS")
+	}
+
+	dnsnames := make(map[string]bool)
+	dnsnames[uc.Router.DNS] = true
+
+	for i, other := range uc.Others {
+		if other.DNS == "" {
+			return fmt.Errorf("other record #%d has no DNS", i)
+		}
+		if dnsnames[other.DNS] {
+			return fmt.Errorf("the DNS FQDN %s is used twice", other.DNS)
+		}
+		dnsnames[other.DNS] = true
+		if !other.NFT.ValidateSetNames() {
+			return fmt.Errorf("other %s NFT set names invalid (probably identical for v4 and v6)", other.DNS)
+		}
+		if other.V6IID == "" {
+			return fmt.Errorf("other record %s has no V6IID", other.DNS)
+		}
+		iidIP := net.ParseIP(other.V6IID)
+		if iidIP == nil {
+			return fmt.Errorf("other record %s has invalid V6IID %s", other.DNS, other.V6IID)
+		}
+		if iidIP.To4() != nil {
+			return fmt.Errorf("other record %s IID looks like an IPv4 Address", other.DNS)
+		}
+	}
+
+	return nil
+}
+
 func (uc *UserConfig) PrettyPrint() string {
 	s, err := json.MarshalIndent(uc, "", " ")
 	if err != nil {
diff --git a/users/test.yml b/users/example.yml
similarity index 96%
rename from users/test.yml
rename to users/example.yml
index c04df9e..86a20a2 100644
--- a/users/test.yml
+++ b/users/example.yml
@@ -1,4 +1,3 @@
-username: test
 password: $2a$10$ymHFfGjKINWsUKwEo5xp.efN6DR6NkiRCXsbH4VWo0Nnzma8Yc.82
 router: 
   DNS: brandfeld.dyn.local
diff --git a/webapi/server.go b/webapi/server.go
index e1b3e34..e85678d 100644
--- a/webapi/server.go
+++ b/webapi/server.go
@@ -5,19 +5,18 @@ import (
 	"log"
 	"net/http"
 
-	"gitea.nehmer.net/torben/dyndns/service"
 	"github.com/gorilla/mux"
 )
 
-func Server() {
-	r := mux.NewRouter()
-	r.StrictSlash(true)
+var router = mux.NewRouter()
 
-	r.HandleFunc("/hello", handleHello)
-	r.HandleFunc("/update", handleUpdate)
+func Server() {
+	router.StrictSlash(true)
+
+	router.HandleFunc("/hello", handleHello)
 
 	log.Printf("Listening to: %s", C.ListenAddress)
-	go log.Fatal(http.ListenAndServe(C.ListenAddress, r))
+	go log.Fatal(http.ListenAndServe(C.ListenAddress, router))
 }
 
 func handleHello(w http.ResponseWriter, r *http.Request) {
@@ -28,43 +27,3 @@ func handleHello(w http.ResponseWriter, r *http.Request) {
 	log.Println(r.Form)
 	fmt.Fprint(w, "<html><body><p>Hello World</p></body></html>")
 }
-
-func handleUpdate(w http.ResponseWriter, r *http.Request) {
-	err := r.ParseForm()
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusBadRequest)
-		return
-	}
-
-	ur, err := createUpdateRequestFromForm(r.Form)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusBadRequest)
-		return
-	}
-
-	uc, err := service.LoadConfigForUser(ur.UserName, ur.Password)
-	if err != nil {
-		if _, ok := err.(*service.UnauthorizedError); ok {
-			http.Error(w, err.Error(), http.StatusUnauthorized)
-		} else {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-		}
-		return
-	}
-	v := uc.DB
-
-	w.Header().Set("Content-Type", "text/plain")
-	fmt.Fprintln(w, "OK")
-	fmt.Fprintln(w, ur.PrettyPrint())
-	log.Println(ur.PrettyPrint())
-	log.Println(ur.IPv6Net.IP)
-	log.Println(ur.IPv6Net.Mask)
-	log.Println(v.AllSettings())
-	log.Printf("Request PW: %s, Config PW: %s", ur.Password, v.GetString("password"))
-	fmt.Fprintln(w, "Unmarshalled userconfig:")
-	fmt.Fprintln(w, uc.PrettyPrint())
-	fmt.Fprintln(w, "WebAPI Config:")
-	fmt.Fprintln(w, C.PrettyPrint())
-	fmt.Fprintln(w, "Service Config:")
-	fmt.Fprintln(w, service.C.PrettyPrint())
-}
diff --git a/webapi/update.go b/webapi/update.go
new file mode 100644
index 0000000..2130226
--- /dev/null
+++ b/webapi/update.go
@@ -0,0 +1,58 @@
+package webapi
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	"gitea.nehmer.net/torben/dyndns/service"
+)
+
+func init() {
+	router.HandleFunc("/update", handleUpdate)
+}
+
+func handleUpdate(w http.ResponseWriter, r *http.Request) {
+	err := r.ParseForm()
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	ur, err := createUpdateRequestFromForm(r.Form)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	uc, err := service.LoadConfigForUser(ur.UserName, ur.Password)
+	if err != nil {
+		if _, ok := err.(*service.UnauthorizedError); ok {
+			http.Error(w, err.Error(), http.StatusUnauthorized)
+		} else {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+		}
+		log.Printf("Authorization failed: %v", err)
+		return
+	}
+
+	w.Header().Set("Content-Type", "text/plain")
+	fmt.Fprintln(w, "OK")
+	fmt.Fprintln(w, ur.PrettyPrint())
+	log.Println(ur.PrettyPrint())
+	log.Println(ur.IPv6Net.IP)
+	log.Println(ur.IPv6Net.Mask)
+	log.Printf("Request PW: %s, Config PW: %s", ur.Password, uc.PassWord)
+	fmt.Fprintln(w, "Unmarshalled userconfig:")
+	fmt.Fprintln(w, uc.PrettyPrint())
+	fmt.Fprintln(w, "WebAPI Config:")
+	fmt.Fprintln(w, C.PrettyPrint())
+	fmt.Fprintln(w, "Service Config:")
+	fmt.Fprintln(w, service.C.PrettyPrint())
+
+	for _, other := range uc.Others {
+		log.Printf("Other %s, IID %v, UR V6NEt: %v, merged: %v",
+			other.DNS, other.V6IID, ur.IPv6Net,
+			other.ConvertIIDToAddress(ur.IPv6Net))
+	}
+}
diff --git a/webapi/updaterequest.go b/webapi/updaterequest.go
index 72fbd3c..56bd722 100644
--- a/webapi/updaterequest.go
+++ b/webapi/updaterequest.go
@@ -10,18 +10,16 @@ import (
 )
 
 type UpdateRequest struct {
-	IPv4      net.IP
-	IPv6      net.IP
-	UserName  string
-	Password  string
-	Domain    string
-	DualStack bool
-	IPv6Net   *net.IPNet
+	IPv4     net.IP
+	IPv6     net.IP
+	UserName string
+	Password string
+	IPv6Net  *net.IPNet
 }
 
 func (ur *UpdateRequest) String() string {
-	return fmt.Sprintf("IPv4: %v, IPv6: %v, UserName: %v, Password: %v, Domain: %v, DualStack: %v, IPv6Net: %v",
-		ur.IPv4, ur.IPv6, ur.UserName, ur.Password, ur.Domain, ur.DualStack, ur.IPv6Net)
+	return fmt.Sprintf("IPv4: %v, IPv6: %v, UserName: %v, Password: %v, IPv6Net: %v",
+		ur.IPv4, ur.IPv6, ur.UserName, ur.Password, ur.IPv6Net)
 }
 
 func (ur *UpdateRequest) PrettyPrint() string {
@@ -57,17 +55,6 @@ func createUpdateRequestFromForm(form url.Values) (*UpdateRequest, error) {
 		return nil, errors.New("a Password must be specified")
 	}
 
-	ur.Domain = form.Get("Domain")
-	if ur.Domain == "" {
-		return nil, errors.New("a Domain must be specified")
-	}
-
-	if form.Get("DualStack") == "1" {
-		ur.DualStack = true
-	} else {
-		ur.DualStack = false
-	}
-
 	if ip6net := form.Get("IPv6Net"); ip6net != "" {
 		_, ipnet, err := net.ParseCIDR(ip6net)
 		if err != nil {