Hi,

not a ball breaker - as everything still works... afaict.

on my quad intel cards I get all IP packets with bad cksums when
viewing via tcpdump - pf enabled or not!

capabilities=7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx,TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>

% ifconfig wm3 tcp4csum udp4csum tso4 ip4csum
[[wait 34 seconds! poor sockets ]]

enabled=3f80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx>

then:

19:05 hadrian:~% sudo tcpdump -enlv -i wm3 |grep bad\ cksum
[snip]
19:05:33.916096 00:15:17:14:ee:19 > 00:00:0c:07:ac:fb, ethertype IPv4 (0x0800), length 66: (tos 0x0, ttl  63, id 60320, offset 0, flags [DF], proto: TCP (6), length: 52, bad cksum 0 (->ea78)!) 193.34.28.23.57249 > 146.101.246.11.3306: ., cksum 0x4e88 (correct), ack 0 win 16746 <nop,nop,timestamp 109171399 3172525958>
[snip]

what does that mean? cksum 0??

so I port spanned the traffic back to the same NIC, wm4, and of course
*no* bad cksums.

19:05 hadrian:~% sudo ifconfig wm3 -ip4csum
19:07 hadrian:~% sudo tcpdump -enlv -i wm3 |grep bad\ cksum
tcpdump: listening on wm3, link-type EN10MB (Ethernet), capture size 96
bytes
^C25313 packets captured
104115 packets received by filter
77966 packets dropped by kernel

all gone! can someone explain?

http://www.intel.com/network/connectivity/products/pro1000pt_quad_server_adapter.htm

19:15 hadrian:~% grep wm3 /var/run/dmesg.boot 
wm3 at pci8 dev 0 function 1: Intel PRO/1000 QT (82571EB), rev. 6
wm3: interrupting at ioapic0 pin 17 (irq 5)
wm3: PCI-Express bus
wm3: 65536 word (16 address bits) SPI EEPROM
wm3: Ethernet address 00:15:17:14:ee:19
igphy1 at wm3 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0

-- 
 hail eris
 http://rubberduck.com/