diff --git a/src/cap_utils.c b/src/cap_utils.c
index 4a21f4a..4d3724c 100644
--- a/src/cap_utils.c
+++ b/src/cap_utils.c
@@ -38,3 +38,6 @@ size_t cap_count_bp(struct cap_file *cf) {
 void cap_unload(struct cap_file *cf) {
   fclose(cf->fd);
 }
+void cap_begin(struct cap_file *cf) {
+  fseek(cf->fd, 0L, SEEK_SET);
+}
diff --git a/src/cap_utils.h b/src/cap_utils.h
index e4ea634..0c97f6e 100644
--- a/src/cap_utils.h
+++ b/src/cap_utils.h
@@ -16,4 +16,5 @@ void cap_next_bp(struct cap_file *cf, struct buffer_packet* bp);
 void cap_peek_bp(struct cap_file *cf, struct buffer_packet* bp);
 void cap_npeek_bp(struct cap_file *cf, int c, struct buffer_packet* bp);
 size_t cap_count_bp(struct cap_file *cf);
+void cap_begin(struct cap_file *cf);
 void cap_unload(struct cap_file *cf);
diff --git a/src/capreplay.c b/src/capreplay.c
index fdec439..d84873f 100644
--- a/src/capreplay.c
+++ b/src/capreplay.c
@@ -1,8 +1,21 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <glib-2.0/glib.h>
+#include <glib-2.0/gmodule.h>
+#include <glib-2.0/glib-object.h>
 #include "cap_utils.h"
 #include "net_tools.h"
 
+void get_ports(struct cap_file *cf) {
+  struct buffer_packet bp;
+  size_t entry_count = cap_count_bp (cf);
+  for (int c = 0; c < entry_count; c++) {
+    cap_next_bp (cf, &bp);
+    int a = bp.ip.ap.fmt.content.clear.port;
+  }
+  cap_begin(cf);
+}
+
 int main(int argc, char** argv) {
   setvbuf(stdout, NULL, _IONBF, 0);
   printf("~ capreplay ~\n");
@@ -28,24 +41,37 @@ int main(int argc, char** argv) {
       }
   }
 
-  struct cap_file cf;
-  cap_load(&cf, inf);
+  struct cap_file cf_in, cf_out;
+  cap_load(&cf_in, inf);
+  cap_load(&cf_out, outf);
 
-  size_t nbp = cap_count_bp (&cf);
-  if (nbp < 1) {
+  size_t nbp_in = cap_count_bp (&cf_in);
+  size_t nbp_out = cap_count_bp (&cf_out);
+  if (nbp_in < 1 || nbp_out < 1) {
     fprintf(stderr, "No buffer packet to read\n");
     exit(EXIT_FAILURE);
   }
 
-  struct timespec started;
+  struct timespec started_rcv, started_snd;
   struct buffer_packet bp;
-  cap_peek_bp (&cf, &bp);
-  started = bp.seen;
 
-  int fd = create_udp_client ("127.0.0.1", "5000");
+  // 1. init listening
+  // 2. check if I should start
+  // 3.
 
-  for (int c = 0; c < nbp; c++) {
-    cap_next_bp (&cf, &bp);
+  cap_peek_bp (&cf_in, &bp); started_rcv = bp.seen;
+  cap_peek_bp (&cf_out, &bp); started_snd = bp.seen;
+  if (started_rcv.tv_sec < started_snd.tv_sec ||
+      (started_rcv.tv_sec == started_snd.tv_sec && started_rcv.tv_nsec < started_snd.tv_nsec)) {
+    // We need to wait to receive some packets before emitting as we are a server
+  } else {
+    // We are a client and we must emit packets now
+  }
+
+  //int fd = create_udp_client ("127.0.0.1", "5000");
+
+  for (int c = 0; c < nbp_in; c++) {
+    cap_next_bp (&cf_in, &bp);
     //sleep(bp.seen);
     // send on UDP to 127.13.3.7
     // sleep for given time