IP Address and Domain Name System

Service Description: 

Hosting and management of static or dynamic IPv4 and IPv6 address assignments and their respective domain name records (DNS) within the OIT managed address space.

Aliases: 
Service Levels: 

System Availability: 24x7

Support Hours: 24x7

Change requests are fulfilled within 24 hours.

Maintenance:
The following maintenance windows are reserved for installing, repairing and patching various components of this service:

  • Every Tue, 5:00AM - 7:00AM EST
  • Every Thu, 5:00AM - 7:00AM EST
  • The third Sat of each month, 6:00AM - 12:00PM EST
Requirements: 

This service is restricted to pre-approved IT staff.

If you are an end-user in need of assistance with IP address or DNS assignments, please contact your local IT support staff.

Charges: 

Free of Charge

Support Information: 

NOTE: This service is unable to provide DHCP for private non-routable address ranges. Units supporting such an environment must operate a local DNS/DHCP appliance to satisfy that need.

New Zones and Networks

OIT also fields requests for new zones or networks. In some cases, domain names containing a dot (.) may be added to the gatech.edu domain instead of adding a new zone.  This should only be done if the same-as-zone record must be a CNAME, such as when pointing to a GTM hostname for failover.  In addition, there must not be more than 3 hostnames per third-level domain created in this way.  For example, new.gatech.edu is required to point to new.gtm.gatech.edu for failover.  The DNS administrator then might add new, www.new, and test.new to the gatech.edu domain.  This is not an ideal configuration, and requesters are urged to consider using a name within an assigned third-level zone to point to a GTM domain name.

Deployment of Changes

Most changes to DNS should propagate to the DNS servers in no more than 10-15 minutes.  Some more complex changes may take up to an hour.  If an hour passes and your completed change request has not propagated, please contact support@oit.gatech.edu so that the problem can be investigated.

Situations to Avoid
  • All CERT entries must be valid.
  • Third-level zones and gatech.edu records may not have the same name.
  • Any requested names of questionable nature or otherwise incompatible with Institute core values may be denied.
  • Any requested names containing profanity will be denied.
  • IP addresses which have more than one A record must only have one reverse record corresponding to the CNAME for that IP address.
Independent Name Servers

Departments may run their own DNS server, although it is discouraged.  The names of the servers must be provided along with the zones for which the servers should be authoritative. Zone transfers and name resolution must be allowed for all Institute nameservers.  Restricting zone transfers and name resolution as much as possible is advised for security reasons.

External Domains and IP addresses

Adding external domains to the nameservers and pointing gatech.edu names to external IP addresses is allowed.

Please note that we are not a registrar.  You must obtain the domain name from an external entity if you wish to use Georgia Tech’s IPAM system to manage the names.

Documentation: 

DNS, or Domain Name System, translates a network host name that is easy to remember (such as www.gatech.edu) to a network IP (Internet Protocol) address (for example, 130.207.244.120) that is not so easy to remember, but which is necessary for computers and other equipment on a network to communicate. The three most common types of DNS records are the following:

  • A or Address Record - Translates a host name to an IP address
  • CNAME or Canonical Name Record - Aliases one host name to another host name
  • PTR or Pointer Record - Translates an IP address to a host name

There are many other types of DNS records, but these are by far the most used.

Campus DNS Servers

The following servers should be used when statically configuring a client's DNS settings.

Client or Workstation:

  • 130.207.244.251 (brahma1.dns.gatech.edu)
  • 130.207.244.244 (brahma2.dns.gatech.edu)
  • 128.61.244.254 (brahma3.dns.gatech.edu)

Server residing within OIT Rich Data Center:

  • 130.207.165.140 (brahma4.dns.gatech.edu)
  • 128.61.244.232    (brahma7.dns.gatech.edu)
  • 128.61.244.254    (brahma3.dns.gatech.edu)

Server residing within OIT BCDC Data Center:

  • 128.61.244.232  (brahma7.dns.gatech.edu)
  • 128.61.244.254  (brahma3.dns.gatech.edu)
  • 130.207.165.140 (brahma4.dns.gatech.edu)

 NOTE: Computers on the 130.207.244.0/24 CANNOT use the 130.207.244.244 or the 130.207.244.251 anycast servers. Please configure your machines with brahma4 (130.207.165.140), brahma7 (128.61.244.232), and brahma3 (128.61.244.254).

 Delegated DNS Servers

For External Domain, ex: example.com, that has our DNS servers, dns1-3, as the authoritative, please make sure to configure:

  • dns1.gatech.edu (128.61.244.253)
  • dns2.gatech.edu (52.72.26.168)
  • dns3.gatech.edu (168.24.2.35)

For those departments running their own master DNS servers in campus network, please configure the following as slave servers and zone notifies to:

  • dns1.gatech.edu (128.61.244.253)
  • dns2.gatech.edu (10.128.22.155)
  • dns3.gatech.edu (168.24.2.35)

Please also allow zone transfer requests from the following networks:

  • 130.207.244.0/24
  • 128.61.244.0/24
  • 130.207.165.0/24
  • 143.215.251.0/26
  • 168.24.2.32/27
Dynamic Host Configuration

DHCP, or Dynamic Host Configuration Protocol, allows a network host to obtain an IP address dynamically (i.e. as needed when connected to the network), instead of requiring that an IP address be set statically (i.e. to a constant value) on the host itself. There are three ways in which DHCP can give IP addresses to hosts:

  1. DHCP Reserved - This allows a host to always retain the same IP address, much as if it were assigned statically. The IP address for the host is assigned according to the host's MAC (Media Access Control) address, which is unique to its physical network interface or adapter.
  2. DHCP Range - This allows any computer to be assigned an IP address and communicate on a network as long as there are free (i.e. unused) IP addresses in the defined range. Computers will not necessarily retain the same IP each time they connect to the network.
  3. Static - Not a form of DHCP record per se, but rather the terminology used to indicate that a particular address is not assigned by DHCP.

A number of factors determines which of these methods should be used, including the level of security desired and whether the host must be accessible via a fixed host name. In general, however, DHCP allows an administrator to easily manage and change network address assignments for hosts on their network, and if desired, to limit which systems are allowed on the network.

Taken together, DNS and DHCP services provide the IP address management (IPAM) required for Georgia Tech's networks to operate, and for local and remote users to access networked IT resources at Georgia Tech's campuses.

Both DNS and DHCP are administered through the BlueCat Networks IPAM appliances, whose user interface is accessible to authorized Georgia Tech IT personnel at gtipam.dns.gatech.edu.

Audience: 
Service Category: 

Infrastructure

Core enterprise-level IT infrastructure that provides underlying support for institutional activities. Includes network backbone, data centers, virtualization, and central storage and backup solutions.

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