Frequently Asked Questions

well, not really, but they could be

How much does a dynamic address cost? The MIT network is cost recovered on a per machine basis. Depending on who you are the actual mechanism may vary but it usually takes the form of tracking the IP address. The purpose of this registration system is to provide a means of tracking hosts whose IP addresses are changing. There is no additional cost above and beyond the rates you would normally pay for your machine.

It says my computer isn't registered. If your host name was recently assigned, wait over night for that information to propagate here. If you are using a host name that's been around for a while, double check that the IP address you are using matches that hostname.

Should I use DHCP for my desktop computers as well? You could, but there's no benefit considering you need to statically configure it to register. Another consideration is that as dhcp implementations shake out their bugs, and we ours, you're probably better off for the time being statically configuring the computers you are not regularly moving, especially if you need them to function in unattended operation. As time goes on we will likely change this philosophy as technologies mature and we update our administrative processes.

If my service provider at home supports DHCP, do I need to do anything to move my laptop back and forth? We've had good experiences with service providers such as MediaOne (warning: annoying home page) but our experience outside MIT is limited (RCN, you too can be linked here if you enable my service already). We'd appreciate knowing how it goes.

What if my host name or address changes, do I need to re-register? No, with an exception (there's always one of those). The short story is that the database record itself cannot change. If a name or address change is performed by renaming the existing record (ie: hostname-old) and creating a new one then that host will have to re-register.

How can I know if there's a network drop there? There's about 15,000 UTP ethernet drops on campus and still growing so your chances are ok. For the past few years we have been outfitting classrooms and common spaces for this type of use however there are areas that have little networking available. For a list of network drops you can consult the drop report (warning: huge file) but the formatting is a bit crude but probably good enough to do a search on.

I registered and reconfigured my laptop but why can't I get an IP address? We're still working to enable DHCP where we can on the MIT campus. Consult the rollout list to see if your location is listed. If it is then please use the feedback form to submit a bug report.

Why can't I get my hostname to follow me around campus? There are efforts within the IETF to try and make this happen, but it's still a ways away from prime time.

Why do I seem to get more name lookup failures while using DHCP? Macintoshes using OpenTransport don't appear to be configuring all 3 of MIT's name servers. The name servers are each taken out of service for a few minutes for updating one or more times daily and the correct behavior is to use one of the other available name servers. We're trying to track down this problem.

DHCP stopped working for me. DHCP is keyed to your MAC address. If your MAC address changes (the cpu board was replaced by the vendor, for example, meeroh) you will need to re-register.


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