diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 9e041fa5c545367961f03fa8a9124aebbc1b6c69..44c09eddbb781c03da2417aaa925e360de01a6e9 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2517,6 +2517,12 @@ static int __net_init tcp_sk_init(struct net *net)
 		if (res)
 			goto fail;
 		sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
+
+		/* Please enforce IP_DF and IPID==0 for RST and
+		 * ACK sent in SYN-RECV and TIME-WAIT state.
+		 */
+		inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
+
 		*per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
 	}