Hello all,


Just for the record, I have a Broadcom NetLink Gigabit Ethernet NIC with PCI IDs V14E4 (Broadcom, obviously), D1693.  My Windows XP driver is b57xp32.sys.


I had encountered an issue where I could ping and perform any sort of UDP to my hosted coLinux, but TCP wasn’t working.  My coLinux’ service had parameters something like:


  --run-service coLinux kernel=vmlinux cobd0=c:\somepath\Ubuntu_2GB.ext3 root=/dev/cobd0 eth0=pcap-bridge,Wired,00:0c:29:ab:ad:7e,promisc


So I was obviously using WinPcap bridging.  I tried updating to the latest WinPcap, but it didn’t fix the problem.  Wireshark revealed a lot of duplicate TCP ACKs and invalid checksums, so I checked the properties for the Broadcom NIC.  In the Advanced tab of its properties, I had Checksum Offload set to Tx/Rx TCP/IP Checksum.  I set it to None and the problem disappeared and TCP communications now work as expected.  I had not encountered this problem on some other hardware.


Just putting this out there as a solution, in case anyone can benefit.  Dunno if it’s FAQ-worthy; possibly not.


- Shao Miller