/etc/hosts should be short and sweet, but is not deprecated. Tom asked: > Is entries in the /etc/hosts file, really required? > Or is it "older" technology, that normally is replaced by some other > function?
You want to use DNS as much as possible because network maint is much easier that way. But DNS imposes a layer (the lookup) for which some response times may see a measurable increase. "It depends." Contemporary Linux systems (probably applies to most Unix) should have at least two entries in /etc/hosts: one for the local machine with its local ethernet (or CTC or whatever) address, and another for "localhost" with the 127.0.0.1 loop-back address. Some systems also like to have the name and address of the nearest YP server as well and/or a major file server if one is used heavily. /etc/hosts can speed up some kinds of access (eg: NFS and YP). But there is the obvious problem of [re]deploying a fully-populated /etc/hosts file to every system in a changing network. I like to have a standard "hosts.txt" (same format as /etc/hosts) on a common web server or file server for reference, which would ease the deployment problem, but I AVOID using it unless there is some problem that might call for it. The internet itself was driven by a massive /etc/hosts file until DNS was invented (now more than fifteen years ago, I guess). Deployment of that names file was a pain. It did not scale. But there are occasions when one or two "hint names" are useful, like the address of the local machine. > Now when I look at it, it would seem to be requried. After all, I'm > naming this node on the network. Right. But naming this node in /etc/hosts only serves this node. That file is not consulted when this host tries to identify itself (eg: via DHCP if a specific host NAME is requested). But it IS consulted when applications (eg: Oracle?) refer to this host by its reachable address (and not via the "loop back" addr). > But, I also thought that when I created the Host Name, and Name Server > Configuration, during the install, a default entry in the /etc/hosts > file would have been setup, if this was such an important entry. This is an installation program feecher (or failure). There is no stopping an app from using /etc/hosts as an API. Sure, better to go thru the standard functions (now all in GLIBC). But even there, why bounce off a DNS server for your own name? It's a sysadmin call: Your network, your rules. -- R; ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
