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.


Please forgive some further detail: Only TCP communications between the host and the hosted coLinux were affected.  TCP communications between the hosted coLinux and any other computer were fine all along.  It was quite irritating having to use another computer as a stepping-stone to get back to the hosted coLinux. J


- Shao Miller