A few missed SYN's

[Poul-Henning Kamp]

I'm seeing a few cases were we fail to reply to a SYN, but we are
talking 3 cases in 5 minutes at 50mbit/sec load.

%grep 129.241.138.93.15578 /tmp/_syns
1156070576.840399 IP 129.241.138.93.15578 > 10.0.2.21.80:
	S 2999862850:2999862850(0) win 5840 <mss 1460>
1156070579.849804 IP 129.241.138.93.15578 > 10.0.2.21.80:
	S 2999862850:2999862850(0) win 5840 <mss 1460>
1156070579.849821 IP 10.0.2.21.80 > 129.241.138.93.15578:
	S 3653626228:3653626228(0) ack 2999862851 win 65535 <mss 1460>
1156070579.849951 IP 129.241.138.93.15578 > 10.0.2.21.80:
	. ack 1 win 5840
1156070579.849953 IP 129.241.138.93.15578 > 10.0.2.21.80: 
	P 1:550(549) ack 1 win 5840
1156070579.850091 IP 10.0.2.21.80 > 129.241.138.93.15578: 
	P 1:153(152) ack 550 win 65535
1156070579.858764 IP 129.241.138.93.15578 > 10.0.2.21.80: 
	. ack 153 win 6432
1156070583.851173 IP 10.0.2.21.80 > 129.241.138.93.15578: 
	F 153:153(0) ack 550 win 65535
1156070583.860066 IP 129.241.138.93.15578 > 10.0.2.21.80: 
	F 550:550(0) ack 154 win 6432
1156070583.860086 IP 10.0.2.21.80 > 129.241.138.93.15578: 
	. ack 551 win 65534

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.