IP Addressing on ISUnet
What is an IP address?
  To obtain access to or host Internet resources from on campus, an IP 
  (Internet Protocol) address must be defined on a computer system to 
  provide accessibility on ISUnet. This address must be unique throughout
  the Internet in order for these applications to work properly and to 
  prevent one computer system from conflicting with another. At the same
  time, an IP address identifies the affiliation that the computer has with 
  the network it is connected to. Consult the document entitled 
  ISUnet Conventions and Standards for more information about 
  addressing.
Static Addressing
  A static IP address is manually defined to a computer. It is the 
  responsibility of the computer support professional to manage the
  address space that they have been assigned. If you need to request new
  or additional address space, click on the link below.

  IP Address Space Request Form
Dynamic Addressing using DHCP
  By August 21, 2000, all campus-based academic, administrative, and
  residential (ResNet) networks at Illinois State University as well as 
  off-campus residential ADSL, Greek house, and affiliated apartment 
  complex networks will support the use of dynamic IP addressing through
  a service called DHCP (Dynamic Host Configuration Protocol). This 
  service allows a user to obtain an IP address and related configuration 
  information (ie: gateway, subnet mask, DNS server addresses, and 
  WINS server addresses) without the need for statically defining them. 

  It is important to understand that private IP addresses will be served 
  using DHCP. This means that computers using DHCP can connect to any 
  on and off-campus Internet site. A computer using DHCP cannot host 
  services (ie: web, FTP, etc) to off-campus users. However, a computer 
  using DHCP can host services to any other computer connected to 
  academic, administrative, and residential (ResNet) networks at Illinois 
  State University as well as off-campus residential ADSL and Greek 
  house networks.

  Registration
    In an effort to prevent unauthorized access to University or Internet 
    network resources or services, all users must register their computers 
    to obtain IP addressing information from the campus DHCP servers. 
    To register a computer, it must first be configured to use DHCP (under
    Windows, select Obtain IP address from server). It is important that 
    no DNS, gateway address, or WINS server addresses are defined. 
    After the computer is restarted, launch a web browser such as 
    Netscape or Internet Explorer. If the computer has never been 
    registered before or the registration has expired, a registration form 
    will appear within the browser (regardless of what URL was 
    referenced). To complete the registration, the user must specify a valid
    ULID and password. If the ULID and password are valid, the ethernet
    address of your computer is automatically captured and placed into a
    security database. This database is used to determine if you can be 
    served an IP address through DHCP. If you need help or have any 
    questions about this process, please contact the University Helpdesk 
    at 438-help.

  Address Lease Periods
    After registration is complete, you will need to reboot your computer.
    You may alternatively manually release and renew your IP address 
    lease through the use of utilities such as winipcfg (Win95 or 98) or
    ipconfig (WinNT or 2000). You have five minutes to complete the 
    registration before it expires. Once you have registered, you will be 
    served an IP address with a 30 day lease period. If this computer has 
    not been online within this 30 day window, your computer will 
    automatically request a new IP address lease the next time it boots up. 
    No user intervention is required. Typically, the IP address that has 
    been served to it will be reused if it hasn't been assigned to another 
    computer.

  IP Mobility
    A major benefit of DHCP is mobility. If a computer tends be mobile 
    (ie: laptop or notebook), DHCP makes it easy for the user to get online
    as the computer is connected from one network to the next. Most 
    implementations of DHCP allow a computer to automatically request a
    new IP address lease at bootup if the current address being leased is 
    invalid on the network that the computer is attached to.

  De-Registration
    To ensure that the registration database remains current, a computer 
    can also be de-registered. This allows a computer to be re-registered 
    to another user if needed. There are two ways to de-register your 
    computer. The first is through a de-registration web based form. Click
    the link below to use this form.

    DHCP De-Registration Form

    The second method is through auto-expiration. If you are a student, a 
    computer registration will be expired automatically at the end of each 
    spring semester and just before the beginning of each fall semester. 
    The dates and times for these expirations will be posted on this 
    website. If you are a faculty, staff, or emeritus, a computer registration
    will expire after one year. You will receive an email notification prior
    to the expiration. If you need help or have any questions about this 
    process, please contact the University Helpdek at 438-help.
Dynamic vs Static Addressing
  DHCP is useful in environments that are unmanaged (ie: ResNet and 
  off-campus ADSL) or for users that have a need to be mobile between 
  multiple networks. Users that reside on ResNet and off-campus ADSL 
  networks are required to use DHCP to prevent address conflicts and 
  automate the recovery and management of unused addresses. We 
  strongly recommend that DHCP only be used in the environments 
  mentioned above or when a user has mobility needs with a laptop or 
  notebook computer.

  Static addressing is useful for computers that aren't mobile. All 
  computers that host services on and off-campus must use a static 
  address. 

  If you are unsure as which technique you should you for obtaining an IP
  address, please contact TNSS for assistance at 438-8731.

Last updated 9/3/2000.
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