diff --git a/src/core/tcp.c b/src/core/tcp.c
index ae7a1214..814d2564 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -1715,8 +1715,8 @@ tcp_alloc(u8_t prio)
     /* As initial send MSS, we use TCP_MSS but limit it to 536.
        The send MSS is updated when an MSS option is received. */
     pcb->mss = INITIAL_MSS;
-    pcb->rto = 500 / TCP_SLOW_INTERVAL;
-    pcb->sv = 500 / TCP_SLOW_INTERVAL;
+    pcb->rto = 1500 / TCP_SLOW_INTERVAL;
+    pcb->sv = 1500 / TCP_SLOW_INTERVAL;
     pcb->rtime = -1;
     pcb->cwnd = 1;
     pcb->tmr = tcp_ticks;