IP address variable

[Bill Gradwohl]

John Miller wrote:

>
> The hosts file is for (more-or less) permanently-assigned addresses.  
> Yes, it's unneeded for dynamic (DHCP-assigned) addresses.
>
You can do that if you like, but it makes little sense if you have a DNS 
server handy.

If you have 100 machines, and they all have permanently assigned IP 
addresses, are you saying you're going to stuff 100 lines of name to 
address mappings into each machines hosts file? If yes, then what do you 
think DNS is for?

With DNS, I make one change and I update every machines name to address 
mapping view of the local network.

> Well, pre-DNS, for sure, but I wouldn't go so far as to call it a 
> relic.  It's just the ticket for those addresses that are nailed 
> down.  Many admins like to do that for some or all of their local 
> machines.  (Your own /etc/host.conf file still includes something like 
> "order hosts bind," doesn't it?)

The concept of hosts came before DNS, and therefore it has a legacy 
foothold on systems. It had a real use as you suggest in the pre DNS 
days. Today, changing hosts files for name resolution is antiquated and 
the hosts.conf was augmented to specify bind as an additional mechanism; 
the preferred mechanism.

I dare say that DNS is the defacto name resolver database today, and 
that almost no one uses hosts to provide anything past resolving 
localhost which does indeed resolve to 127.0 type addresses and are 
unique per box. Therefore DNS can't resolve localhost and hence hosts is 
the only place to resolve it.

-- 
Bill Gradwohl
bill at ycc.com
http://www.ycc.com
spamSTOMPER Protected email