diff --git a/desync.c b/desync.c
index e6368cb..fb6232a 100644
--- a/desync.c
+++ b/desync.c
@@ -76,9 +76,46 @@ static inline void delay(long ms)
 #define delay(ms) Sleep(ms)
 #endif
 
+#ifdef __linux__
+void wait_send(int sfd)
+{
+    for (int i = 0; params.wait_send; i++) {
+        struct {
+            uint8_t state;
+            uint8_t r[3];
+            uint32_t rr[35];
+            uint32_t notsent_bytes;
+        } tcpi = {};
+        socklen_t ts = sizeof(tcpi);
+        if (getsockopt(sfd, IPPROTO_TCP,
+                TCP_INFO, (char *)&tcpi, &ts) < 0) {
+            perror("getsockopt TCP_INFO");
+            break;
+        }
+        if (ts < sizeof(tcpi)) {
+            LOG(LOG_E, "tcpi_notsent_bytes not provided\n");
+            params.wait_send = 0;
+            break;
+        }
+        if (tcpi.state != 1) {
+            LOG(LOG_E, "state: %d\n", tcpi.state);
+            return;
+        }
+        if (tcpi.notsent_bytes == 0) {
+            return;
+        }
+        LOG(LOG_S, "not sent after %d ms\n", i);
+        delay(1);
+    }
+    delay(params.sfdelay);
+}
+#else
+#define wait_send(sfd) delay(params.sfdelay)
+#endif
+
 #ifdef __linux__
 int send_fake(int sfd, char *buffer,
-        int cnt, long pos, int fa, int ttl)
+        int cnt, long pos, int fa, struct desync_params *opt)
 {
     struct packet pkt = cnt != IS_HTTP ? fake_tls : fake_http;
     size_t psz = pkt.size;
@@ -104,19 +141,31 @@ int send_fake(int sfd, char *buffer,
         }
         memcpy(p, pkt.data, psz < pos ? psz : pos);
         
-        if (setttl(sfd, ttl, fa) < 0) {
+        if (setttl(sfd, opt->ttl ? opt->ttl : 8, fa) < 0) {
+            break;
+        }
+        if (opt->ip_options
+            && setsockopt(sfd, IPPROTO_IP, IP_OPTIONS,
+                opt->ip_options, opt->ip_options_len) < 0) {
+            perror("setsockopt IP_OPTIONS");
             break;
         }
         if (sendfile(sfd, ffd, 0, pos) < 0) {
             uniperror("sendfile");
             break;
         }
-        delay(params.sfdelay);
+        wait_send(sfd);
         memcpy(p, buffer, pos);
         
         if (setttl(sfd, params.def_ttl, fa) < 0) {
             break;
         }
+        if (opt->ip_options
+            && setsockopt(sfd, IPPROTO_IP,
+                IP_OPTIONS, opt->ip_options, 0) < 0) {
+            perror("setsockopt IP_OPTIONS");
+            break;
+        }
         status = 0;
     }
     if (p) munmap(p, pos);
@@ -127,7 +176,7 @@ int send_fake(int sfd, char *buffer,
 
 #ifdef _WIN32
 int send_fake(int sfd, char *buffer,
-        int cnt, long pos, int fa, int ttl)
+        int cnt, long pos, int fa, struct desync_params *opt)
 {
     struct packet pkt = cnt != IS_HTTP ? fake_tls : fake_http;
     size_t psz = pkt.size;
@@ -180,7 +229,13 @@ int send_fake(int sfd, char *buffer,
             uniperror("SetFilePointer");
             break;
         }
-        if (setttl(sfd, ttl, fa) < 0) {
+        if (setttl(sfd, opt->ttl ? opt->ttl : 8, fa) < 0) {
+            break;
+        }
+        if (opt->ip_options
+            && setsockopt(sfd, IPPROTO_IP, IP_OPTIONS,
+                opt->ip_options, opt->ip_options_len) < 0) {
+            perror("setsockopt IP_OPTIONS");
             break;
         }
         if (!TransmitFile(sfd, hfile, pos, pos, &ov, 
@@ -204,6 +259,12 @@ int send_fake(int sfd, char *buffer,
         if (setttl(sfd, params.def_ttl, fa) < 0) {
             break;
         }
+        if (opt->ip_options
+            && setsockopt(sfd, IPPROTO_IP, IP_OPTIONS,
+                opt->ip_options, 0) < 0) {
+            perror("setsockopt IP_OPTIONS");
+            break;
+        }
         status = 0;
     }
     if (!CloseHandle(hfile)) {
@@ -231,17 +292,14 @@ int send_oob(int sfd, char *buffer,
         return -1;
     }
     buffer[pos] = rchar;
-    if (size) {
-        delay(params.sfdelay);
-    }
+    wait_send(sfd);
+    
     for (long i = 0; i < size; i++) {
         if (send(sfd, data + i, 1, MSG_OOB) < 0) {
             uniperror("send");
             return -1;
         }
-        if (size != 1) {
-            delay(params.sfdelay);
-        }
+        wait_send(sfd);
     }
     return 0;
 }
@@ -267,7 +325,7 @@ int send_disorder(int sfd,
 }
 
 
-int desync(int sfd, char *buffer, size_t bfsize,
+ssize_t desync(int sfd, char *buffer, size_t bfsize,
         ssize_t n, ssize_t offset, struct sockaddr *dst, int dp_c)
 {
     struct desync_params dp = params.dp[dp_c];
@@ -364,7 +422,7 @@ int desync(int sfd, char *buffer, size_t bfsize,
         #ifdef FAKE_SUPPORT
         case DESYNC_FAKE:
             s = send_fake(sfd, 
-                buffer + lp, type, pos - lp, fa, dp.ttl ? dp.ttl : 8);
+                buffer + lp, type, pos - lp, fa, &dp);
             break;
         #endif
         case DESYNC_DISORDER:
diff --git a/desync.h b/desync.h
index 0ea058b..9e480e9 100644
--- a/desync.h
+++ b/desync.h
@@ -1 +1 @@
-int desync(int sfd, char *buffer, size_t bfsize, ssize_t n, ssize_t offset, struct sockaddr *dst, int dp_c);
+ssize_t desync(int sfd, char *buffer, size_t bfsize, ssize_t n, ssize_t offset, struct sockaddr *dst, int dp_c);
diff --git a/main.c b/main.c
index 30fcae7..289adeb 100644
--- a/main.c
+++ b/main.c
@@ -39,6 +39,7 @@ oob_data = {
 
 struct params params = {
     .sfdelay = 3,
+    .wait_send = 1,
     .def_ttl = 0,
     .custom_ttl = 0,
     .de_known = 0,
@@ -85,6 +86,7 @@ const char help_text[] = {
     #ifdef FAKE_SUPPORT
     "    -f, --fake <n[+s]>        Split and send fake packet\n"
     "    -t, --ttl <num>           TTL of fake packets, default 8\n"
+    "    -k, --ip-opt <f|:str>     IP options of fake packets\n"
     "    -l, --fake-tls <f|:str>\n"
     "    -j, --fake-http <f|:str>  Set custom fake packet\n"
     "    -n, --tls-sni <str>       Change SNI in fake ClientHello\n"
@@ -123,6 +125,7 @@ const struct option options[] = {
     #ifdef FAKE_SUPPORT
     {"fake",          1, 0, 'f'},
     {"ttl",           1, 0, 't'},
+    {"ip-opt",        1, 0, 'k'},
     {"fake-tls",      1, 0, 'l'},
     {"fake-http",     1, 0, 'j'},
     {"tls-sni",       1, 0, 'n'},
@@ -132,6 +135,7 @@ const struct option options[] = {
     {"tlsrec",        1, 0, 'r'},
     {"def-ttl",       1, 0, 'g'},
     {"delay",         1, 0, 'w'}, //
+    {"not-wait-send", 1, 0, 'W'}, //
     {0}
 };
     
@@ -484,6 +488,14 @@ int main(int argc, char **argv)
                 dp->ttl = val;
             break;
             
+        case 'k':
+            dp->ip_options = ftob(optarg, &dp->ip_options_len);
+            if (!dp->ip_options) {
+                uniperror("read/parse");
+                return -1;
+            }
+            break;
+            
         case 'n':
             if (change_tls_sni(optarg, fake_tls.data, fake_tls.size)) {
                 fprintf(stderr, "error chsni\n");
@@ -567,7 +579,11 @@ int main(int argc, char **argv)
                     || params.sfdelay >= 1000 || *end)
                 invalid = 1;
             break;
-
+        
+        case 'W':
+            params.wait_send = 0;
+            break;
+            
         case 0:
             break;
             
diff --git a/params.h b/params.h
index 7276229..17f9e39 100644
--- a/params.h
+++ b/params.h
@@ -31,6 +31,8 @@ struct part {
 
 struct desync_params {
     int ttl;
+    char *ip_options;
+    ssize_t ip_options_len;
     int parts_n;
     struct part *parts;
     int mod_http;
@@ -43,6 +45,7 @@ struct params {
     int dp_count;
     struct desync_params *dp;
     long sfdelay;
+    char wait_send;
     int def_ttl;
     char custom_ttl;
     
diff --git a/proxy.c b/proxy.c
index ccb9789..f181179 100644
--- a/proxy.c
+++ b/proxy.c
@@ -350,6 +350,9 @@ int create_conn(struct poolhd *pool,
         return -1;
     }
     int status = connect(sfd, &addr.sa, sizeof(addr));
+    if (status == 0 && params.tfo) {
+        LOG(LOG_S, "TFO supported!\n");
+    }
     if (status < 0 && 
             get_e() != EINPROGRESS && get_e() != EAGAIN) {
         uniperror("connect");
@@ -733,7 +736,7 @@ int on_desync(struct poolhd *pool, struct eval *val,
     if (sn < 0) {
         return -1;
     }
-    if (sn != n) {
+    if (sn < n) {
         val->buff.offset = sn;
         if (mod_etype(pool, val->pair, POLLOUT, 1)) {
             uniperror("mod_etype");