diff --git a/.gitignore b/.gitignore
index c9566ca..f57c870 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@
 *.d
 cachesyncd
 cachesyncd.log
+cachesync.sock
+testclient
diff --git a/Makefile b/Makefile
index ac4ad37..c88643e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,14 +1,17 @@
 # Toplevel Makefile
 
-SRC := cachesyncd.c configfile.c logging.c multicast.c unixsock.c
+SRC := cachesyncd.c configfile.c logging.c multicast.c selector.c unixsock.c
 CFLAGS := -O2 -Wall
 
 # ############################
 
-all: cachesyncd
+all: cachesyncd testclient
 
 cachesyncd: $(SRC:%.c=%.o)
-	$(CC) $(LDFLAGS) $^ -o $@
+	$(CC) $(CFLAGS) $^ -o $@
+
+testclient: testclient.o
+	$(CC) $(CFLAGS) $^ -o $@
 
 %.d: %.c
 	$(CC) $(CFLAGS) -MM -c $< -o $@
@@ -17,6 +20,6 @@ cachesyncd: $(SRC:%.c=%.o)
 	$(CC) $(CFLAGS) -o $@ -c $<
 
 clean:
-	rm -rf *.d *.o cachesyncd
+	rm -rf *.d *.o cachesyncd cachesyncd.log cachesync.sock
 
 -include $(SRC:.c=.d)
diff --git a/cachesyncd.c b/cachesyncd.c
index 86f91c4..1baec61 100644
--- a/cachesyncd.c
+++ b/cachesyncd.c
@@ -27,8 +27,7 @@
 
 #include "configfile.h"
 #include "logging.h"
-#include "multicast.h"
-#include "unixsock.h"
+#include "selector.h"
 
 #define DEFAULT_CONFIG "cachesyncd.conf"
 #define DEFAULT_LOGFILE "cachesyncd.log"
@@ -40,18 +39,6 @@ static struct option opts[] = {
 	{0, 0, 0, 0}
 };
 
-static void run()
-{
-	int usock, msock;
-	usock = sock_init();
-	msock = mcast_init();
-
-	mcast_send(msock, "HALLO", 6);
-
-	msock_close(msock);
-	sock_close(usock);
-}
-
 int main(int argc, char *argv[])
 {
 	char *config = DEFAULT_CONFIG;
@@ -105,7 +92,7 @@ int main(int argc, char *argv[])
 
 	log_print(LOG_EVERYTIME, "cachesyncd started (pid: %d)", getpid());
 
-	run();
+	selector();
 
 	return 0;
 }
diff --git a/multicast.c b/multicast.c
index 0369970..227d094 100644
--- a/multicast.c
+++ b/multicast.c
@@ -96,6 +96,13 @@ int mcast_init()
 		return -1;
 	}
 
+	char loop = 0;
+	if (setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop))) {
+		log_print(LOG_WARN, "mcast_init: setsockopt(IP_MULTICAST_LOOP)");
+		close(sockfd);
+		return -1;
+	}
+
 	inet_aton(mcastgroup, &multiaddr.imr_multiaddr);
 	multiaddr.imr_interface.s_addr = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
 
diff --git a/selector.c b/selector.c
new file mode 100644
index 0000000..1afd5be
--- /dev/null
+++ b/selector.c
@@ -0,0 +1,101 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include "logging.h"
+#include "multicast.h"
+#include "unixsock.h"
+
+#define BUF_SIZE 256
+
+void selector()
+{
+	fd_set fdsel;
+
+	char *buf = malloc(BUF_SIZE);
+	if (buf == NULL) {
+		log_print(LOG_ERROR, "selector: out of memory");
+		return;
+	}
+
+	int usock = sock_init();
+	if (usock < 0)
+		return;
+
+	int msock = mcast_init();
+	if (msock < 0)
+		return;
+
+	int usock_con = -1;
+
+	while (1) {
+		struct timeval tv;
+
+		FD_ZERO(&fdsel);
+		FD_SET(usock, &fdsel);
+		FD_SET(msock, &fdsel);
+
+		if (usock_con != -1)
+			FD_SET(usock_con, &fdsel);
+
+		tv.tv_sec = 60;
+		tv.tv_usec = 0;
+
+		int ret = select(64, &fdsel, NULL, NULL, &tv);
+		if (ret < 0) {
+			log_print(LOG_ERROR, "selector: select()");
+			continue;
+
+		} else if (ret == 0) {
+			mcast_send(msock, "KEEPALIVE", 10);
+
+		} else if (FD_ISSET(usock, &fdsel)) {
+			if (usock_con != -1) {
+				log_print(LOG_INFO, "selector: unix socket overflow");
+				close(usock_con);
+			}
+
+			usock_con = accept(usock, NULL, NULL);
+			if (usock_con == -1)
+				log_print(LOG_ERROR, "selector: accept()");
+
+		} else if (usock_con != -1 && FD_ISSET(usock_con, &fdsel)) {
+			int len = read(usock_con, buf, BUF_SIZE);
+			if (len > 0)
+				mcast_send(msock, buf, len);
+
+			if (!strncmp(buf, "DELETE ", 7)) {
+				log_print(LOG_DEBUG, "delete '%s'", buf +7);
+				// exec unlink
+
+			} else {
+				log_print(LOG_DEBUG, "recv unknown cmd via unix socket: '%s'", buf);
+			}
+
+			close(usock_con);
+			usock_con = -1;
+
+		} else if (FD_ISSET(msock, &fdsel)) {
+			int len = read(msock, buf, BUF_SIZE);
+			if (len <= 0) {
+				log_print(LOG_ERROR, "selector: multicast sock closed?");
+
+			} else if (!strncmp(buf, "KEEPALIVE", 10)) {
+
+			} else if (!strncmp(buf, "DELETE ", 7)) {
+				log_print(LOG_DEBUG, "delete '%s'", buf +7);
+				// exec unlink
+
+			} else {
+				log_print(LOG_DEBUG, "recv unknown cmd via multicast: '%s'", buf);
+			}
+		}
+	}
+
+	msock_close(msock);
+	sock_close(usock);
+}
diff --git a/selector.h b/selector.h
new file mode 100644
index 0000000..b9540d8
--- /dev/null
+++ b/selector.h
@@ -0,0 +1,6 @@
+#ifndef _SELECTOR_H_
+#define _SELECTOR_H_
+
+void selector();
+
+#endif // _SELECTOR_H_
diff --git a/testclient.c b/testclient.c
new file mode 100644
index 0000000..d50057c
--- /dev/null
+++ b/testclient.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#define FILENAME "cachesync.sock"
+
+int main(int argc, char *argv[])
+{
+	if (argc != 2) {
+		printf("$ testclient <cmd>\n");
+		exit(0);
+	}
+
+	int sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (sockfd == -1) {
+		perror("socket()");
+		exit(-1);
+	}
+
+	struct sockaddr_un addr;
+	addr.sun_family = AF_UNIX;
+	strncpy(addr.sun_path, FILENAME, sizeof(addr.sun_path));
+	int len = sizeof(addr.sun_family) + strlen(addr.sun_path);
+
+	if (connect(sockfd, (struct sockaddr *)&addr, len) < 0) {
+		perror("connect()");
+		exit(-1);
+	}
+
+	write(sockfd, argv[1], strlen(argv[1]) +1);
+	close(sockfd);
+
+	return 0;
+}
diff --git a/unixsock.c b/unixsock.c
index d8d203c..670d53b 100644
--- a/unixsock.c
+++ b/unixsock.c
@@ -55,6 +55,13 @@ int sock_init()
 		return -1;
 	}
 
+	ret = listen(sockfd, 5);
+	if (ret == -1) {
+		log_print(LOG_ERROR, "unixsock: listen()");
+		close(sockfd);
+		return -1;
+	}
+
 	return sockfd;
 }