FreeBSD is occasionally not replying to ICMP packets...

[Tim Pozar]

Sending to a FreeBSD 8.0 RELEASE box from a cisco switch that the BSD
box is directly connected to...

> cs01-200p-sfo#ping netmon repeat 1024
> 
> Type escape sequence to abort.
> Sending 1024, 100-byte ICMP Echos to 207.241.239.174, timeout is 2 seconds:
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!
> Success rate is 99 percent (1019/1024), round-trip min/avg/max = 1/2/9 ms
> cs01-200p-sfo#

On the BSD box I see it not replying every 200 pings....

# tcpdump -i bge0 icmp and host 10.1.0.33
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on bge0, link-type EN10MB (Ethernet), capture size 96 bytes
10:55:14.095509 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 0, length 80
10:55:14.095526 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 0, length 80
[...]
10:55:14.658113 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 198, length 80
10:55:14.658119 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 198, length 80
10:55:14.659467 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 199, length 80
10:55:16.663280 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 200, length 80
10:55:16.663291 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 200, length 80
10:55:16.665421 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 201, length 80
[...]
10:55:17.166991 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 398, length 80
10:55:17.167003 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 398, length 80
10:55:17.169476 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 399, length 80
10:55:19.170156 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 400, length 80
10:55:19.170167 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 400, length 80
10:55:19.171675 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 401, length 80
[...]
10:55:19.676469 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 598, length 80
10:55:19.676474 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 598, length 80
10:55:19.679062 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 599, length 80
10:55:21.677805 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 600, length 80
10:55:21.677817 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 600, length 80
10:55:21.683652 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 601, length 80
[...]
10:55:22.170528 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 797, length 80
10:55:22.172653 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 798, length 80
[...]
10:55:24.730624 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 998, length 80
10:55:24.733990 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 999, length 80
10:55:26.736330 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 1000, length 80
10:55:26.736343 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 1000, length 80
10:55:26.739407 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 1001, length 80
10:55:26.739417 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 1001, length 80
[...]
10:55:26.808634 IP 10.1.0.33 > 207.241.239.174: ICMP echo request, id
14, seq 1023, length 80
10:55:26.808643 IP 207.241.239.174 > 10.1.0.33: ICMP echo reply, id 14,
seq 1023, length 80

I don't see this behaviour on other non-BSD devices on this network such
as a Linux box that is also directly connected to this switch.

Thoughts?

Thanks...
Tim