That was a great explaination. I printed that one out to save it. That is what I thought. DNS was suppose to take care of it. So, now I know DNS doesn't take care of everything.
Without my host name in the /etc/hosts file, Oracle, running on that machine, apparently couldn't connect it itself. 127.0.0.1 was there, but not my 192.168.193.231 address. I am going to update my notes so that the hosts file is updated to include the host info for that machine. (I'll let DNS handle the rest.) Tom Duerbusch THD Consulting (Why did Dracula take cold medicine? To stop his "coffin") >>> [EMAIL PROTECTED] 10/31/05 11:33 AM >>> /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 ---------------------------------------------------------------------- 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
