Getting IP addresses

There are three ways to get IP addresses for your workstations or servers. One is automatic and the other two require human intervention and registration. We obviously prefer that you obtain an IP address automatically. That way you can take a new computer out of the box, put it together, plug it into the network, and start using it immediately. The three methods are:

	Comments	Obtained
DHCP	Dynamic Host Configuration Protocol	Automatically
M-DHCP	Requires Application for Manual DHCP	Hybrid
BOOTP	Required Application for BOOTP	Hybrid
Static	Requires Application for manual or static	Manually

If you can use normal DHCP, please do so. Your computer name gets automatically registered in DNS and it requires no manual actions on anyone's part. If you feel that you have special addressing needs, please read on. Then, if you still feel you have special addressing needs, you may apply for an address by calling Mark Harsen or by opening a Special Address Technical Support case with Networking which is described in the "How do I get one" section on this page.

DHCP - Dynamic Host Configuration Protocol

DHCP was created to meet the needs of the ever-evolving and changing needs of work stations and servers on the network. It was becoming unruly and impossible for network personnel to manually administer the thousands or tens of thousands of computers and addresses for an organization.

DHCP was invented to alleviate this problem. Basically, most computers are already configured, out of the box, to use DHCP. Therefore, you simply take your new computer out of the box, put it together, plug it into the network, and it starts working. Every computer has a name which can be changed by the owner of that machine. The configured name is sent as part of the DHCP request and, if not already taken, that name becomes the name or DNS name for your computer. If the name is taken, the system automatically adds a string to the end of the name to make it unique.

Many people think they need a special address that never changes for their web server, their file server, a Polycom video conferencing unit, or some other specific project. While there are some cases where special addressing needs do exist, the above mentioned are not among them. As long a computer system is online at least once a week, it's IP address will not change. If the IP address does change for a system, the DNS name will be kept up to date and point to the new IP address.

Therefore, everything that uses DNS, which is almost every Internet application, need not obtain an IP address through any other method other than our standard DHCP. This also leaves the users or system administrators free to move their machines around at will. Different networks, and thus different IP addresses, are used around campus and between campuses. Users must reapply for manual or hybrid addresses if the systems are moved to a different VLAN. Using standard DHCP, machines may be moved around campus or across campuses to Springfield, West Plains, Mt. Grove, or even Lebanon without any special actions having to be taken.

Also, if anything on the network changes, users automatically and transparently receive the new information. The machines run without interruption and without the knowledge that some networking stuff behind the walls changed. Other forms of addressing are not so fortunate.

What about Manual or Reserved DHCP addresses?

M-DHCP, Manual DHCP and a "DHCP Reservation" are different names for the same thing. Rarely, a special need exists where it is imperative that an IP address change as little as possible or where multiple DNS names must be associated with the same server. A web server hosting many home pages through different DNS names is a classical example of this. To accomplish this, nothing changes on the users machine. It is left configured to use DHCP, but specific information about the machine is given to Networking that we use to configure our DHCP servers. They will always give out the same address and have the same DNS aliases associated with the address.

If the user moves the machine, however, Networking must be contacted ahead of time to facilitate the move. It's a rather simple process, but failure to do it could result in loss of service to the moved resource.

BOOTP - Bootstrap Protocol

BOOTP was actually the predecessor of DHCP and DHCP is built on the foundation of BOOTP. It is a much older and bulkier attempt to solve the massive addressing problems presented by the Internet Protocol (IP). Users are strongly encouraged to steer clear of BOOTP in favor of DHCP or at least a Manual DHCP address. However, there are still some old systems on the network that do not support any from of DHCP. For those systems, we recommend BOOTP where it is supported. The only systems known to exist that need BOOTP are some cash registers, old Windows 3.11 machines, and old Macintoshes running MAC/TCP. Our recommendation would be to upgrade these machine where possible for these and other reasons.

BOOTP sends a specific request to a central server and expects networking configuration information to be sent to the machine. It configures itself, and attaches properly to the network. Registering a machine to use BOOTP is almost exactly the same as with M-DHCP, but the host name is fixed and can only be changed by Networking at the request of the owner. It is less reliable than DHCP, but shares the advantage that behind the scenes changes are maintained by Networking and the user never need to be concerned by network addressing or topology changes. If the user moves the machine to another VLAN, it must be re-registered.

Statically or Manually Configured

We like this form of addressing least of all. It requires registration of the address and it requires that the all network information, not just the station's IP address, be manually or "hard-coded" into the software on the machine. If the machine moves or if something behind the scenes change, it is most likely that any machine that has a static address will quit working.

We most often get requests from owners of Linux, Sun OS, or other variants of the Unix operating system for static addresses. It is true that most versions of Unix cannot support anything other than static addresses. We hope the Unix industry will someday recognize this flaw and reform as indeed many vendors of Linux already have.

Can't I just find an unused address and use it for myself?

Absolutely not. Missouri State University Networking owns and assigns all IP addresses that start with 146.7. Just because an address is not currently in use as indicated by repeated pings or other methods, doesn't mean that Networking won't assign the address months, days, or even seconds later. Using IP addresses illegally in this manner will cause severe problems for the legal owner of the address. These could be anything from intermittent network drops to a totally unusable system.

Using an IP address illegally is a severe offense. Anyone using an address not obtained automatically via DHCP or obtained through a successful application for a special address is breaking University Policy. Such violations could result in all networking services to the offending machine being immediately terminated without prior notice. Other, more severe sanctions could also be levied.

I still think I need a special address. How do I get one?

The process of requesting a special address is quite simple, but the need must clearly be established before the request will be granted. The easiest way is to contact Mark Harsen and to have an open dialogue regarding your needs. The best addressing scheme can then be picked and the machine can immediately be registered. This consists of getting several pieces of information about the machine and about the person who is responsible for the machine. Anyone not choosing to use DHCP, however, assumes all responsibility for contacting Networking should their IP address stop working for any reason.

A web interface is also provided to request a special address should the user desire. While it is very efficient, many users are overwhelmed by the amount of information needed and may not understand exactly what is being asked for or where to find it. Therefore, we highly recommend simply calling Mark Harsen to ask for a special address.

How do I get an IP address for my computer or server at Missouri State University facilities? I think I have special needs.