As an addendum, I just used "ethtool" in order to turn off NIC-based checksumming on the bonded interface and then tried tcpdump again on the FTP real server. This time, all the checksums came back as "correct".
So the checksums are correct. I was suspicious that all of the outgoing packets had bad checksums - particularly seeing as port 21 also had this, yet the FTP commands besides uploading work fine - so I thought I'd remove the possibility of it being NIC-based checksumming causing it and see if there's any packets left as "incorrect" afterwards ("grep incorrect"). There isn't. All the checksums are fine. Regards, Owain _______________________________________________ Please read the documentation before posting - it's available at: http://www.linuxvirtualserver.org/ LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org Send requests to lvs-users-requ...@linuxvirtualserver.org or go to http://lists.graemef.net/mailman/listinfo/lvs-users