Special Issue

The Great Address and Domain Name Conversion

Newsletter Archive:

        http://www.chemistry.ohio-state.edu/compsupp/Newsletter/

Due to the many hyperlinks, COMPNEWS is best viewed on the web
at the above URL, or by going to the main Chemistry page and
clicking on Internal --> Computer Support --> The Newsletter Archive



Due the important nature of this project, this will be the only topic in this
special issue of COMPNEWS. As you have probably already gathered from the
lack of COMPNEWS since December 1, we have been extremely busy (to put it
mildly), literally fighting against floods and burning UPS units... We have
been working on several time-intensive projects (many of them rather
invisible to our user community) that are all designed to upgrade our
computer systems and make our network more useful.

We mentioned this project in the last issue of COMPNEWS. We have to change IP
addresses for all computers in the Department. At the same time, we are
leaving the mps.ohio-state.edu domain and will move into the new
chemistry.ohio-state.edu domain.


Reasons for the change:


The exact reason for this transition is very technical and not easy to
explain. We are currently occupying 4 non-adjacent class-C IP subnets
(128.146.20.0, 128.146.33.0, 128.146.182.0, 128.146.190.0). Each class-C
subnet contains 255 IP-addresses. OIT has given us 4 new adjacent subnets
(128.146.232.0 - 128.146.235.0) and expects us to vacate the old ones soon.
Currently, OIT has to run a special service (called proxy ARP) to let us
experience the 4 non-adjacent subnets like one big subnet. OIT doesn't want
to offer this service much longer. With the new adjacent subnets, the address
range conveniently fits into bit-boundaries, and our network will be like
"one big happy subnet" without OIT having to do anything special. It is very
important to be "one big happy subnet", because things like NetBIOS-based
browsing of network shares and protecting the Department with a firewall
won't work otherwise.

If you want to try out the technical explanation, see

  Internal --> Computer Support --> Support Bulletin News -->
           --> Reasons for the IP-address change

It is important to note that this move is not something that we want to do.
We HAVE to make the transition, whether we like it or not. We would rather
not, since it will inconvenience many of you, and some things may break
during the transition period, regardless of how much testing we do
beforehand.


Consequences of the change:


Once the change is made, there will be few if any consequences. All our
computers will live in the CHEMISTRY domain, i.e. they will have addresses of
the form

  host.chemistry.ohio-state.edu

Currently, they are all named host.mps.ohio-state.edu.

Of course, our email addresses will not change; they will continue to be
username@chemistry.ohio-state.edu. The URL for the Chemistry Home Page will
remain at www.chemistry.ohio-state.edu. All interactive logins into the
Department go through the chemistry Unix server, which will continue to be
chemistry.ohio-state.edu. To be more precise, chemistry.ohio-state.edu will
continue to be one possible name for our Unix server. It has yet to be
determined if the hostname proper (the name you get when you run the command
'hostname') will need to be changed.

(There will be changes on the Windows side because of the transition to
Windows2000 fileservers, but those changes are not related to the
address/domain change and will be discussed in the next regular issue of
COMPNEWS.)

As part of the transition, we will move most PCs and Macs in the Department
to DHCP (Dynamic Host Configuration Protocol). Whenever a computer boots,
it will request an IP-address dynamically. This scheme allows for a much
more efficient use of the available addresses. Only server-type machines
will have statically (permanently) assigned IP-addresses.

The reorganization of the address space will also allow us to simplify
firewall rules. For example, no access from outside the Department will be
needed for desktop-type client computers using DHCP, i.e. for the vast
majority of all computers in the Department. This does not affect outgoing
connections, only incoming access to services (desktop client computers by
definition don't run any services).


What do YOU need to do?


If you operate Mac, PC or Unix clients and you don't depend on any services
being reachable from outside the Department (FTP, HTTP [webserver], NetBIOS
[Windows filesharing], Appletalk, Timbuktu, PC Anywhere), you don't need to
do anything.

If you have a department-related need to run any of the above services on
your computer, you need to make a request NOW. Since we offer FTP, webservice
and Windows filesharing on the central departmental servers, there is no need
for most of you to run your own servers. If you are a student, and you have
been running a webserver on your PC, you need to move your web pages onto the
chemistry Unix server. Research group home pages also need to reside on the
Unix server.

If you have a Unix machine that we don't control, we need root access to make
the necessary changes.

As a general reminder: our web address is

   www.chemistry.ohio-state.edu

and NOT chemistry.ohio-state.edu. This has always been the case. Even though
presently chemistry.ohio-state.edu and WWW.chemistry.ohio-state.edu are
one-and-the-same computer, this may not always be the case. To insure that
URLs you give to others (like in your email-signature files) continue to
work in the future, it is important to use the WWW address for the web
server.

We look forward to helping you through this transition. As always,
communication is key to this goal. If you have any questions about this
transition, please contact us. We will attempt to accomodate you, but we
can't do anything about it if you don't tell us.

Due to the disruptive nature of this transition, it has been scheduled for
Spring Break (week of March 19). We will start by migrating the Unix server,
then we'll change the clients over a period of a few days, trying to minimize
disruptions. There is still a lot of work that needs to be finished before
we can attempt this transition.


A few FAQs:


Q: The name "host.chemistry.ohio-state.edu" is longer than
   "host.mps.ohio-state.edu"; do I have to type the longer name now?

A: If you are inside the Department, all the computers are in the same
   domain, and it is sufficient to type "host" whenever you connect to an
   internal computer, just as is the case now. But from outside the domain
   chemistry.ohio-state.edu, you will have to use the whole name (the fully
   qualified domain name), as you do now.


Q: I'm in the Physics Department, and I normally just type "ssh chemistry".
   Will this command still work?

A: Yes, this command will still work. Even though Physics is in the MPS
   domain and we will be in the CHEMISTRY domain, the name
   "chemistry.mps.ohio-state.edu" (implicit when using the hostname
   "chemistry" from within the MPS domain) will still be recognized.


Q: My web URL is www.chemistry.ohio-state.edu/~username; will this URL
   remain the same?

A: Yes, this URL will remain unchanged. Just make sure you don't forget the
   "www" before "chemistry"!


Q: I'm running a webserver for my personal homepage and an FTP server on my
   PC; will I continue to be able to do that?

A: No, you need to move your web pages to the Unix server. We can increase
   your disk quota if you need more space for your web pages. The Unix server
   also allows FTP, anonymous and regular, from inside and outside the
   Department. If you have an FTP archive that needs to be accessed from
   outside the Department, you should move it to the Unix server as well.
   You would need department-related reasons to run your own webserver; your
   personal homepage is not a legitimate reason.


Q: I understand that I won't be able to access Windows NetBIOS shares on
   my PC from outside the Department. Will I be able to access them from
   other PCs in the Department?

A: While you won't be able to access your NetBIOS shares on your PC from
   outside the Department, you can move data onto your U: share on the
   central Windows fileserver, which is accessible from outside the
   Department (the method how to do this will change in the future, but we
   will always try to maintain this service). You will still be able to
   access NetBIOS shares on your PC from inside the Department, but make
   sure that those shares are PASSWORD PROTECTED and not writeable by just
   anybody! Again you would need department-related reasons if you wanted the
   NetBIOS shares on your PC to be available outside the Department.


Q: If my Windows PC uses DHCP and therefore its name can change every time
   the PC reboots, how can I map my NetBIOS shares from other PCs in the
   Department?

A: NetBIOS uses the NetBIOS name of the PC, not the IP-name. The NetBIOS name
   you give your PC will always stay the same, regardless of the IP-address
   and IP-name that your PC obtains via DHCP; see the DHCP FAQ on our
   webpages:

     Internal --> Computer Support --> Chemistry Department Related FAQs -->
	      --> How do I configure my PC or Mac to use DHCP?