On 12/05/2013 06:04 PM, Bob Proulx wrote: > Russell L. Carter wrote: >> Ok, I need to do some experimenting here. I've broken out a long patch >> cable to bypass the switch > > I would really be surprised if the switch has broken down. Not impossible > of course. But what are the odds? I think it very unlikely. If I were to > guess I would guess it more likely that packets are being routed to the > wrong place. I think that is many times more likely. > >> and am steeling myself for the tcpdump learning experience. > > You will be surprised how easy it is! Just run it. Control-C out of it to > stop it. >
So the awesome foodie in-laws dropped in for a couple of days, and I'm the cook. But I shooed them off this morning and finally got a chance to look at this again. I reconfigured my net to get the DHCP conversation on the least used net, patched the laptop directly to the server, and on the server ran $ tcpdump -lenx -i eth1 -s 1500 port bootps or port bootpc On the laptop I generally use wicd, and I know that works, so to simplify things I just told wicd to connect using DHCP. And it worked! I'd not have such a shiny head today if I had done this months ago, when I first noticed the weirdness. I just used the DD-WRT AP DHCP server so that I could maximize my procrastination metrics. So then the problem was to figure what was awry with the switch, a D-Link DGS-1224T. I thought I had sometime in the distant past lobotomized it but it turns out no, I didn't get it done completely. In particular, IGMP snooping was enabled. I downloaded the switch's manual (thanks D-Link!) and here is what it said: "With Internet Group Management Protocol (IGMP) snooping, the Web-Smart Switch can make intelligent multicast forwarding decisions by examining the contents of each frame’s Layer 2 MAC header. IGMP snooping can help reduce cluttered traffic on the LAN. With IGMP snooping enabled globally, the Web-Smart Switch will forward multicast traffic only to connections that have group members attached." But there were no "group members" defined. Oops. Disabled, applied, power off/on, voilà. Thanks Bob! (I used this tutorial for tcpdump: http://www.danielmiessler.com/study/tcpdump/ I guess I'm a believer now.) > Good luck! > > Bob > -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/[email protected]
