DNS Entries

1
DNS Entries

• Purposes
• Methods
• Windows AD Ramifications

2
DNS Tables

• The DNS table is the resource that replicates
  across several servers to resolve an IP address
  to a Domain Name
• An IP address is 4 octets (ie. 138.87.73.79)
• An octet is one of the 4 fields in an IP
• Those fields may be filled with a number from 0
  to 255 (162 or (2x8)2) hence octet

3
DNS Tables

• This machine (138.87.73.79) is in Edwards Hall,
  Room 303 in the Mennonite College of Nursing
• Using the Domain Naming Conventions for ISU,
  option 4, the machine (NetBIOS) name would be
  MCNEDW303079 (OUN BLD RM OCT)
• The Domain Name for that machine should be
  MCNEDW303079.mcn.ilstu.edu (case does not matter)

4
Purpose of DNS Entries

• Certain resources require a reverse DNS lookup
  that verifies an ISU machines pedigree
• Web servers require a DNS address so that people
  can type something in the location bar besides
  138.87.73.79
• Active Directory assumes ALL units have DNS
  entries NetBIOS and NetBEUI are no longer the
  defacto standard for workgroup routing

5
Expiration of DNS Entries

• Domain Names in the external Internet (ICAAN)
  expire either annually or bi-annually (every one
  or two years)
• ISUs DNS table could be a mess, if we allowed
  many multiple entries to co-exist, so emulating
  the Internet expiration policies is in our best
  interests
• Machine names will not expire, but Custom Web
  Addresses and External Domains will

6
Registering the Machine Name

• Enter your information
• Enter the IP address, the domain name and an
  alias (if needed)
• Submit

7
Registering a Custom Address

• Enter your information
• Enter Custom Web Address, the IP and note the
  existing machine name (if needed)
• Submit

8
Registering an External Domain

• Enter your information
• Enter billing entity (these cost money)
• Enter Custom Web Address, the IP and note the
  existing machine name (if needed)
• Enter grant notes or such
• Submit

9
AD Ramifications

• Active Directory assumes ALL units have DNS
  entries NetBIOS and NetBEUI are no longer the
  defacto standard for workgroup routing
• Non-unique machine domain names will result in
  non-unique DNS calls by AD
• Please refer to the documentation both past and
  present regarding this issue for further
  clarification

10
Homework

• www.tnss.ilstu.edu has the most comprehensive
  info
• It contains current and topical data to assist
  you in your work
• Chapters 67 are directly relevant to todays
  topic
• FIN