diff --git a/client.go b/client.go
index d24dffe..440ca94 100644
--- a/client.go
+++ b/client.go
@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"strings"
 	"time"
 )
 
@@ -83,27 +82,23 @@ Setting up the client / Checking the parameters
 // NewClient generates a new XMPP client, based on Config passed as parameters.
 // If host is not specified, the DNS SRV should be used to find the host from the domainpart of the JID.
 // Default the port to 5222.
-// TODO: better config checks
 func NewClient(config Config, r *Router) (c *Client, err error) {
 	// Parse JID
 	if config.parsedJid, err = NewJid(config.Jid); err != nil {
 		err = errors.New("missing jid")
 		return nil, NewConnError(err, true)
 	}
-	
+
 	if config.Password == "" {
 		err = errors.New("missing password")
 		return nil, NewConnError(err, true)
 	}
-	
+
 	// fallback to jid domain
 	if config.Address == "" {
 		config.Address = config.parsedJid.Domain
 	}
-	// if address has no port (behind his ipv6 address) - add default port
-	if strings.LastIndex(config.Address, ":") <= strings.LastIndex(config.Address, "]") {
-		config.Address += ":5222"
-	}
+	config.Address = ensurePort(config.Address, 5222)
 
 	c = new(Client)
 	c.config = config
diff --git a/network.go b/network.go
new file mode 100644
index 0000000..75a0a60
--- /dev/null
+++ b/network.go
@@ -0,0 +1,32 @@
+package xmpp
+
+import (
+	"strconv"
+	"strings"
+)
+
+// ensurePort adds a port to an address if none are provided.
+// It handles both IPV4 and IPV6 addresses.
+func ensurePort(addr string, port int) string {
+	// This is an IPV6 address literal
+	if strings.HasPrefix(addr, "[") {
+		// if address has no port (behind his ipv6 address) - add default port
+		if strings.LastIndex(addr, ":") <= strings.LastIndex(addr, "]") {
+			return addr + ":" + strconv.Itoa(port)
+		}
+		return addr
+	}
+
+	// This is either an IPV6 address without bracket or an IPV4 address
+	switch strings.Count(addr, ":") {
+	case 0:
+		// This is IPV4 without port
+		return addr + ":" + strconv.Itoa(port)
+	case 1:
+		// This is IPV$ with port
+		return addr
+	default:
+		// This is IPV6 without port, as you need to use bracket with port in IPV6
+		return "[" + addr + "]:" + strconv.Itoa(port)
+	}
+}
diff --git a/network_test.go b/network_test.go
new file mode 100644
index 0000000..840a6f1
--- /dev/null
+++ b/network_test.go
@@ -0,0 +1,35 @@
+package xmpp
+
+import (
+	"testing"
+)
+
+type params struct {
+}
+
+func TestParseAddr(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{name: "ipv4-no-port-1", input: "localhost", want: "localhost:5222"},
+		{name: "ipv4-with-port-1", input: "localhost:5555", want: "localhost:5555"},
+		{name: "ipv4-no-port-2", input: "127.0.0.1", want: "127.0.0.1:5222"},
+		{name: "ipv4-with-port-2", input: "127.0.0.1:5555", want: "127.0.0.1:5555"},
+		{name: "ipv6-no-port-1", input: "1::", want: "[1::]:5222"},
+		{name: "ipv6-no-port-2", input: "[1::]", want: "[1::]:5222"},
+		{name: "ipv6-no-port-3", input: "1::2008", want: "[1::2008]:5222"},
+		{name: "ipv6-no-port-4", input: "1::2008:1", want: "[1::2008:1]:5222"},
+		{name: "ipv6-with-port-1", input: "[1::]:5555", want: "[1::]:5555"},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(st *testing.T) {
+			addr := ensurePort(tc.input, 5222)
+
+			if addr != tc.want {
+				st.Errorf("incorrect Result: %v (!= %v)", addr, tc.want)
+			}
+		})
+	}
+}