On Apr 10, 2009, at 12:48 PM, Henning Schulzrinne wrote: >As part of a research project, we are working on automated >diagnostics of network-related faults in residential, SOHO, >conference/special event, hotel and similar networks. If you have >observed errors that were hard for a lay person to diagnose, whether >due to end system problems, NATs, LAN or Internet issues, please >send me a brief description. (Also, contacts in tech support for I'm not sure if this is the kind of fault you're looking for. In residential networks, often the DSL or Cable "modem" has a misfeature that caches the MAC address of the first device it sees, and won't talk to any others. Often it will only forget the cached MAC address if it's been powered off for a significant time (15 minutes, or an hour). When the ISP's tech sets up a new home, sometimes they come with Windows based software. If the customer doesn't use Windows, the tech will connect their own laptop to run the setup software. Or, the ISP person wants to connect directly rather than through the wireless router. Then the customer tries to use it and it doesn't work, but since the ISP's tech had no problems and reported the Internet connection working, they blame the customer's computer or wireless router. In my experience, I've found that ISP setup people rarely know about this, and often don't understand what "caching the MAC address" means even if you try to explain it to them, to ask if their equipment does it. I think a lot of customers who experience this never figure it out before the problem mysteriously disappears eventually, when they happen to have the thing powered off for a while because they thought it wasn't working. I've also encountered this at other people's homes, where they don't have wireless, and one person's computer gets Internet but the other's doesn't most of the times they try - I've "solved" this problem for other people several times, merely by explaining that they have to power off the dsl/cable box for a certain number of minutes when switching computers (they can figure out how long by experimenting), or by connecting one laptop and sharing its connection to the other via wireless. -- Cos _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf