Hey, I saw something similar a while back, it was caused by loss of packets through a router at the far end of an LFN.
Basically losing like 2% of packets, equated to a drop of 50%-60% in throughput which i thought was rather insane but hey... It was reasonably similar symptoms in that there were *shedloads* of duplicate ACKs, because the network was dropping a packet or two in one direction, and for some reason or other unbeknown to me, it is normal for a device to duplicate an ACK when it receieves packets out of sequence, or is genuinely just missing a packet... or something like that... it was a few months ago now... Bascially i saw improvements by messing around with the MTU, i think i decreased it significantly. I corrected it by replacing the router (actually it was one of those horrible "switch based routers" :-s) HTH -C -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Colin McKinnon Sent: 30 January 2006 21:28 To: SLUG-list Subject: [Scottish] Network notwork Hi all, Obviously my last question just wasn't tough enough....so, this time for a bonus ball... What would cause *lots* of DUP ACKs / Retransmits on a LFN? (10 Mb internet connection, lots of clients at site connecting. 80% + of packets going out to remote server are DUP ACK, 80% + of inward packets are retransmits. Effect is that clients get next to no bandwidth to server. Only occurs with work-related application server - they can access other systems with noi apparrent problem, other sites do not have same problem accessing same server) TIA, C. _______________________________________________ Scottish mailing list Scottish@mailman.lug.org.uk http://mailman.lug.org.uk/mailman/listinfo/scottish ********************************************************************************* This e-mail (and any attachments) is strictly private and confidential and is intended solely for the addressee(s) only. It may contain legally privileged and confidential information. If you are not the intended recipient you must not copy, disclose, distribute or take any action in reliance on this email and must immediately destroy it. Any views or opinions presented are solely those of the originator and do not necessarily represent those of Sanmex International Ltd or any of its affiliates. If you have received this email in error please notify the system manager at the e-mail address [EMAIL PROTECTED] This footnote also confirms that this email message has been checked for the presence of computer viruses. www.sanmex.com ******************************************************************************* _______________________________________________ Scottish mailing list Scottish@mailman.lug.org.uk http://mailman.lug.org.uk/mailman/listinfo/scottish