Today, many individuals and organizations have conventions in place that restrict how a machine or web server can be named. Commonly, underscore characters ( _ ) are used to separate strings and numeric labels, such as SERVER_1234, or to assure that special domain names are not confused with host names. Although the use of underscore characters is effective, they may cause unexpected behavior when you attempt to log in to ArcGIS Server Manager, create services, or manage Web applications using Microsoft Internet Explorer.
Interestingly enough, the origin of this behavior is related to the development of the Domain Name System or “DNS” by Paul Mockapetris in 1983. His spec mandated that the hostname’s labels only contain the letters A – Z, the digits 0 – 9, and the hyphen. No other symbols, punctuation, or blank spaces were permitted. Despite a few modifications to the DNS hierarchy in the past 25 years, underscore characters are still not supported.
You may now be asking yourself, “How does the DNS hierarchy relate to my immediate problem of not being able to open Manager?” Essentially, the DNS acts a phone book for the internet by translating human-friendly machine names into unique numerical identifiers. So, “MyServer” could translate into “123.45.678.910”. When a character, such as an underscore, is introduced into the Web server name, the DNS gets confused since the character does not conform to the DNS hierarchy. Often, this results in failure of the Web server.
In light of this information, we developed the help topic Retaining underscore characters in the Web server name. It provides a workaround that will allow you to preserve your current naming conventions in ArcGIS Server 9.3.1.
Additionally, external topics by IBM and the IETF highlight best-practices when considering host name values and machine naming conventions.
Contributed by Michael Frates, Greg Reeve, and Nikhil Shampur of the ArcGIS Server development team.
