[ActiveDir] DNS vs. Hosts File

[Dan DeStefano]

Recently, one of my colleagues and I got into a discussion about DNS vs. hosts files in AD. He has configured the hosts file on all of our domain controllers (Windows 2000 AD in native mode) to point to other DCs. One of our DCs was moved to another site and the hosts file on a DC was not changed to point to the moved DC on its new subnet – this obviously resulted in NTFRS errors.   Anyway, after this I got into a discussion with my boss about the need of the hosts file in AD. It is my position that the hosts file is no longer necessary and should not really be used in AD and is only included for backward-compatibility, testing and for certain special instances. It is his position that DNS is untrustworthy and that the hosts file should be configured as a backup in case DNS goes down. My response to this was twofold – 1. the hosts file is queried before DNS so it is not really a backup, it is a primary method of name-resolution, plus, it does not support SRV records; 2. DNS is the foundation of AD and if it goes down, AD will not work correctly anyway. Plus, that is the reason for secondary DNS servers, of which we have several.   Could anyone point to any documentation that discusses the role of the hosts file in AD and also include your own opinions and comments. _________________________   Daniel DeStefano PC Support Specialist   IAG Research 345 Park Avenue South, 12th Floor New York, NY 10010 T. 212.871.5262 F. 212.871.5300   www.iagr.net Measuring Ad Effectiveness on Television   The information contained in this communication is confidential, may be privileged and is intended for the exclusive use of the above named addressee(s). If you are not the intended recipient(s), you are expressly prohibited from copying, distributing, disseminating, or in any other way using any of the information contained within this communication. If you have received this communication in error, please contact the sender by telephone 212.871.5262 or by response via e-mail.