On 05 Oct 2002 00:09:39 -0700 James Sparenberg <[EMAIL PROTECTED]> wrote:
> On Thu, 2002-10-03 at 08:10, Mark Stewart wrote: > > > > Networking gurus, your knowledge is desperately needed... > > > > I have my Mdk8.2 box setup on our corporate network with a static > > IP. Call it mybox.foo.com. I have a laptop running Win2K that lives > > on our wireless LAN and uses a DHCP-allocated IP and lives in a > > subnet. Call it laptop.dhcp.foo.com. The trouble is that unless I > > first ping the laptop from mybox, I cannot reach mybox from the > > laptop. More problematically, if I leave an ssh connection from the > > laptop to mybox idle for more than say 5 minutes the connection > > dies. If I reboot into Win2K on mybox I don't have to ping first to > > allow the laptop to connect and connections once made continue to > > work for as long as you like. It just works. > > Had this problem about 2 years ago with an ALL FreeBSD/Win98 network. > with 7 mini-lans in different rooms of our office we noticed that > boxes kept dropping off the net... but never the windows ones. Turned > out that the problem was because FreeBSD and we later found Linux as > well don't keep "chattering" over the net and the Hubs (all switched > 10/100 hubs) kept "losing" the boxes. We'd have to do two way pings > to get the FreeBSD boxes back up every morning...(do a tcpdump > sometime when the network is quite and you'll see your windows boxes > chattering away.) > > The solution. a little script that did 3 pings to the firewall. > Slept for 15 minutes and then did 3 pings again. James, That's a "workaround"... :) the solution is to have the bug fixed... Don't have time to pull up the specs; but any packet for which there is no MAC-to-output-port mapping is to be "flooded" out all ports. If this is not done by a particular switch box, or VLAN, it's a bug. [Sidebar: similar effect occurs when the bridge/switch/VLAN tables are smaller than the number of boxes directly connected -- I call this a "leaky" <foo> box... It's an interesting mental exercise to understand this... :^) ] > Not all of the switched hubs did this (the 3coms for example) but some > of the NetGear and lynksys ones did. NetGear (others?) ships dumb hubs (real ones, not switches labelled "hub") with out-of-spec* crystals which can produce a similar symptom, excect that the problem affects only long packets. * +/- 0.001% i.e., 1000Hz for 10MHz LinkSys have an isolated development group that won't listen to customer complaints. Pierre > James > > > > > Our LAN admin, who clearly knows much more about Windows, is > > pointing the finger at the OS since he isn't required to support > > Linux. Our network has a bunch of VLANs in it, the details to which > > I am not privy but if there's something that might be relevant I can > > ask him about it. On the other hand, if anyone understands what's > > going on here that has to do with how I've got mybox configured I > > would really love to know. Just to be clear, I'm not running any > > firewalls or anything, no iptables, ipchains, etc. I am running NFS, > > Samba, ssh, and proftpd. > > > > Thanks in advance for any and all thoughts, > > > > ::mark > > > > > > ---- > > > > > Want to buy your Pack or Services from MandrakeSoft? > > Go to http://www.mandrakestore.com > > > >
Want to buy your Pack or Services from MandrakeSoft? Go to http://www.mandrakestore.com
