diff --git a/client/client.go b/client/client.go
index 6c0daac..bb06952 100644
--- a/client/client.go
+++ b/client/client.go
@@ -35,14 +35,16 @@ type Context struct {
 	rToServer       chan cm.RFrame
 	initiations     []InitiationInfo
 	initiationsLock sync.RWMutex
+	settings        common.ClientSettings
 }
 
-func NewClientContext(conn *websocket.Conn) *Context {
+func NewClientContext(conn *websocket.Conn, settings common.ClientSettings) *Context {
 	return &Context{
 		conn:          conn,
 		resFromServer: make(chan cm.RFrame),
 		reqFromServer: make(chan cm.RFrame),
 		rToServer:     make(chan cm.RFrame),
+		settings:      settings,
 	}
 }
 
@@ -132,8 +134,6 @@ func (cliCtx *Context) handleStartChatD(reqFrame cm.RFrame) (res cm.Response, er
 
 	logger.Infof("servers wants to be punched, got start chat d request for %s with code %s",
 		startChatDReq.Nickname, startChatDReq.PunchCode)
-	logger.Warn("handleStartChatD not implemented yet")
-
 	idx := slices.IndexFunc(cliCtx.initiations, func(i InitiationInfo) bool {
 		return i.otherSideNick == startChatDReq.Nickname
 	})
@@ -144,7 +144,7 @@ func (cliCtx *Context) handleStartChatD(reqFrame cm.RFrame) (res cm.Response, er
 		return nil, nil
 	}
 
-	conn, err := net.Dial("udp", ":8081")
+	conn, err := net.Dial("udp", cliCtx.settings.UdpAddr)
 	if err != nil {
 		logger.Error("error udp dialing for punch", err)
 		return nil, nil
@@ -247,7 +247,7 @@ func init() {
 }
 
 func sendAuth(ctx *Context, nick, pass string) {
-	logger.Info("trying to authenticate as krzmaciek...")
+	logger.Info("trying to authenticate...", "nick", nick)
 	err := ctx.sendRequest(cm.AuthRequest{Nickname: nick, Password: pass})
 
 	if err != nil {
@@ -344,8 +344,8 @@ func sendStartChatC(ctx *Context, nick string) {
 	logger.Debug("request sent, no wait for response")
 }
 
-func RunClient() {
-	u := url.URL{Scheme: "ws", Host: ":8080", Path: "/wsapi"}
+func RunClient(settings common.ClientSettings) {
+	u := url.URL{Scheme: "ws", Host: settings.WsapiAddr, Path: "/wsapi"}
 	c, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
 
 	if err != nil {
@@ -353,7 +353,7 @@ func RunClient() {
 		return
 	}
 
-	cliCtx := NewClientContext(c)
+	cliCtx := NewClientContext(c, settings)
 	errGroup, syncCtx := errgroup.WithContext(context.Background())
 
 	errGroup.Go(func() error {
diff --git a/common/common.go b/common/common.go
index 116ae5e..8d13b45 100644
--- a/common/common.go
+++ b/common/common.go
@@ -215,3 +215,16 @@ type PunchRequest struct {
 type PunchResponse struct {
 	IPAddr int32 `json:"ipAddr"`
 }
+
+type Settings struct {
+	WsapiAddr string
+	UdpAddr   string
+}
+
+type ServerSettings struct {
+	Settings
+}
+
+type ClientSettings struct {
+	Settings
+}
diff --git a/main.go b/main.go
index 3ef9301..2965c7c 100644
--- a/main.go
+++ b/main.go
@@ -1,28 +1,37 @@
 package main
 
 import (
+	"flag"
 	"log"
-	"os"
 
 	"krzyzanowski.dev/archat/client"
+	"krzyzanowski.dev/archat/common"
 	"krzyzanowski.dev/archat/server"
 )
 
 func main() {
-	args := os.Args[1:]
+	wsapiAddr := flag.String("waddr", ":8080", "An IP address of the websocket API endpoint")
+	udpAddr := flag.String("uaddr", ":8081", "An IP address of the UDP hole-punching listener")
+	runType := flag.String("run", "client", "Either one of 'client' or 'server'")
 
-	if len(args) != 1 {
-		log.Fatalln("You must provide only one argument which is type of " +
-			"application: 'server' or 'client'")
+	flag.Parse()
+
+	commonSettings := common.Settings{
+		WsapiAddr: *wsapiAddr,
+		UdpAddr:   *udpAddr,
 	}
 
-	runType := args[0]
-
-	if runType == "client" {
-		client.RunClient()
-	} else if runType == "server" {
-		server.RunServer()
+	if *runType == "client" {
+		settings := common.ClientSettings{
+			Settings: commonSettings,
+		}
+		client.RunClient(settings)
+	} else if *runType == "server" {
+		settings := common.ServerSettings{
+			Settings: commonSettings,
+		}
+		server.RunServer(settings)
 	} else {
-		log.Fatalf("Unknown run type %s\n", runType)
+		log.Fatalf("Unknown run type %s\n", *runType)
 	}
 }
diff --git a/server/server.go b/server/server.go
index 411c629..4dc6cf6 100644
--- a/server/server.go
+++ b/server/server.go
@@ -698,7 +698,7 @@ func (srvCtx *Context) handleUDP(data []byte, addr net.Addr) {
 	}
 }
 
-func RunServer() {
+func RunServer(settings common.ServerSettings) {
 	srvCtx := NewContext()
 
 	go func() {
@@ -709,16 +709,16 @@ func RunServer() {
 	}()
 
 	http.HandleFunc("/wsapi", srvCtx.wsapiHandler)
-	logger.Info("Starting websocket server...")
+	logger.Infof("Starting websocket server on %s...", settings.WsapiAddr)
 	go func() {
-		err := http.ListenAndServe(":8080", nil)
+		err := http.ListenAndServe(settings.WsapiAddr, nil)
 		if err != nil {
 			logger.Error(err)
 		}
 	}()
 
-	logger.Info("Starting punching server...")
-	listener, err := net.ListenPacket("udp", ":8081")
+	logger.Infof("Starting punching server on %s...", settings.UdpAddr)
+	listener, err := net.ListenPacket("udp", settings.UdpAddr)
 	if err != nil {
 		logger.Error("could not create listener for punching server", err)
 	}