diff --git a/CHANGELOG b/CHANGELOG
index f384f4c7..10d95331 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -196,6 +196,10 @@ HISTORY
 
   ++ Bug fixes:
 
+  2007-06-11 Srinivas Gollakota & Oleg Tyshev
+  * tcp_out.c: Fix for bug #20075 : "A problem with keep-alive timer and TCP flags"
+    where TCP flags wasn't initialized in tcp_keepalive.
+
   2007-06-03 Simon Goldschmidt
   * udp.c: udp_input(): Input pbuf was not freed if pcb had no recv function
     registered, p->payload was modified without modifying p->len if sending
diff --git a/src/core/tcp_out.c b/src/core/tcp_out.c
index 9bc23168..3de9a294 100644
--- a/src/core/tcp_out.c
+++ b/src/core/tcp_out.c
@@ -763,10 +763,11 @@ tcp_keepalive(struct tcp_pcb *pcb)
    tcphdr->dest = htons(pcb->remote_port);
    tcphdr->seqno = htonl(pcb->snd_nxt - 1);
    tcphdr->ackno = htonl(pcb->rcv_nxt);
+   TCPH_FLAGS_SET(tcphdr, 0);
    tcphdr->wnd = htons(pcb->rcv_wnd);
    tcphdr->urgp = 0;
    TCPH_HDRLEN_SET(tcphdr, 5);
-   
+
    tcphdr->chksum = 0;
 #if CHECKSUM_GEN_TCP
    tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip, IP_PROTO_TCP, p->tot_len);