Craig Whitmore wrote:
I was wondering what people think about this latest story..
http://www.idg.net.nz/webhome.nsf/UNID/4AA2988B4A1835C5CC256BFF0014A6A8!open...
(a more technical expanation from Cisco of the problem http://www.cisco.com/warp/public/105/56.html)
How incredibly serendipitous. I just ran into this problem at work the yesterday. The service techs. for our digital radiology system came in and applied the latest service update. All of a sudden users weren't able to log in via their browser loaded Java client. Funny thing is, these guys spent 2 days trying to figure out the problem before resorting to asking "the network guy"... one of those pride things I guess. Some quality time (15 minutes) with tcpdump (well, windump) showed the DF bit being set and repeated acknowledgment requests during the "hang". After a modest amount of investigation and a few phone calls the following was found: 1. a remote firewall blocking all ICMP (the admin won't change it) 2. a router somewhere in the path with a lower MTU requirement 3. a software upgrade forcing the DF bit to be set (developer won't change it) Lowering the MTU on the client end fixed the problem; however, I need to get the registry hack distributed across ~500 desktop and all potentially have different interface descriptions in the HKLM/system/current control set/service/ ...what a PITA. Some additional URLs: http://www.spirit.com/Network/net0700.html http://www.cymru.com/Documents/icmp-messages.html http://www.freelabs.com/~whitis/isp_mistakes.html - To unsubscribe from nznog, send email to majordomo(a)list.waikato.ac.nz where the body of your message reads: unsubscribe nznog