Considerations for DNS Host Name Aliases

These DNS Host Name Alias standards are:

Multiple DNS Aliases may be configured to point to a host name, and these aliases may consist of a variable number of characters, and be names requested by the users or application administrators. However, each DNS alias MUST be an Enterprise Wide Unique (EWU) value to eliminate conflicts during outages, fail-overs, tests, etc. It is recommended that at least one DNS Alias be created using the resource group name which will be used for fail-over procedures.

The reason for using DNS aliases rather than host names is for ease of configuration during fail-overs, either planned or unplanned. Aliases allow the system administrator to easily and quickly redirect users to desired business functions anywhere in the enterprise. This does not require changing IP addresses or renaming resources on any system. It is a simple DNS change and business functions become available. This is especially useful during disaster recovery testing and implementations where fail-over resources may be already provisioned and attached to a network in a remote location. A DNS alias permits the system administrator to point users from one data center to another to reacquire business functions.

The DNS alias name based on the RG name shall consist of exactly 8 characters as shown in table 1:

Application Code + Environment + Function + Company + RG Sequence ID
3 char + 1 char + 1 char + 2 char + 1 char

Table 1: DNS Alias Name Structure based on RG Name

Table 1 illustrates the structure for a DNS Alias naming standard. This structure identifies a DNS Alias name that is 8 characters in length and corresponds with the resource group name associated with this DNS Alias. Some example DNS Alias names are illustrated in Table 2.

Application Code Environment Function Company Code Sequence ID Example Resource Group Name Example DNS Alias Name
ora p d mx 0 orapdmx0 orapdmx0
ora p d mx 1 orapdmx1 orapdmx1
db2 a d ib 0 db2adib0 db2adib0
tib t a hp 8 tibtahp8 tibtahp8
web d a ib 4 webdaib4 webdaib4
apa a a ci 3 apaaaci3 apaaaci3
pag p u mx 0 pagpumx0 pagpumx0

Table 2: Example DNS Alias Names

The policies, guidelines, standards, and procedures set forth in this document for your consideration are as follows: