Re: /bin/hostname
- From: Vwaju <lou@xxxxxxxxxxxxxxxxxxxxx>
- Date: Mon, 25 Aug 2008 12:56:54 -0700 (PDT)
On Aug 23, 5:08 pm, ibupro...@xxxxxxxxxxxxxxxxxxxxxx (Moe Trin) wrote:
On Fri, 22 Aug 2008, in the Usenet newsgroup comp.os.linux.networking, in
article <be279293-c8d6-4ea1-83db-4d5c3782c...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
Vwaju wrote:
NOTE: Posting from groups.google.com (or some web-forums) dramatically
reduces the chance of your post being seen. Find a real news server.
Bit Twister <BitTwis...@xxxxxxxxxxxxxxxx> wrote:
grep jupiter /etc/hosts
127.0.0.1 localhost.localdomain localhost jupiter
207.237.37.110 jupiter.obliqueuniverse.org jupiter
Why do you have jupiter on more than one line. :(
I am working from Linux System Administration (LSA) Adelstein &
Lubanovic, O'Reilly, 2007 (p. 14). LSA is a detailed guide to building
an internet server on Debian Linux ("sarge"), which is what I am
running.
"sarge" (version 3.1) was superseded about a bit over a year ago by
"etch" (version 4.0). Use the command 'cat /etc/debian_version' to see
what you are using. (It's a common problem that printed books are
often dealing with old or even obsolete versions.) Please review the
section about updating the system before you offer an older system to
the bad d00ds on the Internet.
I added the second line (following LSA) because I am building an
internet server with a static IP address, and there needs to be a line
in /etc/hosts that maps the host and the FQDN to the static IP
address.
That is correct, but why is it ALSO a nickname (alias) for localhost?
The concept is that a name appears on one, and only one line in the
/etc/hosts file. Likewise, an IP address should appear on one line
only. Many operating systems will _tolerate_ having the same name or
IP address on multiple lines, but it can give unexpected results.
The 'localhost' alias of 'jupiter' isn't needed. If _ON_ 'jupiter'
you want to send packets to 'jupiter' or 'jupiter.obliqueuniverse.org',
the kernel will look at /etc/host.conf (old applications) or
/etc/nsswitch.conf to see where/how to look up names.
[compton ~]$ grep host /etc/host.conf /etc/nsswitch.conf
/etc/host.conf:order hosts,bind
/etc/nsswitch.conf:hosts: files nis dns
[compton ~]$
Here, both files say to check the /etc/hosts file FIRST. Looking in
your /etc/hosts file, it would find the rcn.com address. But the
kernel is smart, and knows that this address is one of it's addresses
and rather than clutter up the wire with useless noise, it would use
the loopback address - it knows it is talking to itself, not some host
out on the Internet.
then /bin/hostnameshould print "myserver" (the hostname w/o the
domain name)
What do you get on your system?
Linux distributions are supposed to follow Linux Standard Base standards,
and one of those is the Base Core Specification:
------------------
Linux Standard Base Core Specification 3.2
Section 15.2 Command Behavior
Name
hostname -- show or set the system's host name
Synopsis
hostname [name]
Description
hostname is used to either display or, with appropriate privileges, set
the current host name of the system. The host name is used by many
applications to identify the machine.
When called without any arguments, the program displays the name of the
system as returned by the gethostname() function.
When called with a name argument, and the user has appropriate
privilege, the command sets the host name.
Note: It is not specified if the hostname displayed will be a fully
qualified domain name. Applications requiring a particular format of
hostname should check the output and take appropriate action.
------------------
See that note on the end of the requirement? It always is a good idea
to look at the manual page for commands you are unfamiliar with. As Bit
shows in his response, you may get different results depending on which
distribution you are using. And by the way, my systems also return the
FQDN.
Old guy
Thank you for the helpful pointers, Old Guy. I had read the man page
for hostname, but was not aware of the Linux Standard Base Core
Specification 3.2)
Best Regards,
Vwaju
NYC
.
- References:
- Re: /bin/hostname
- From: Bit Twister
- Re: /bin/hostname
- From: Moe Trin
- Re: /bin/hostname
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