If an FTP put works, but get is failing, where should I start in the troubleshooting process? Do you think it's s TCP issue and how can I check?

Does anyone know where I can find a list of which routers and switches support ISL and which don't. I need to know which ones I have to go 802.1q on. Thanks

Is a buffer overflow problem a problem normally associated with not enough NVRAM or memory or a processor issue? What are some good troubleshooting tools for finding out more on this problem