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Old 07-02-2010, 04:34 PM   #1
sneakyimp
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what does /etc/hosts specifying in this particular line?


I'm doing a how-to to setup my debian server. It tells me to edit /etc/hosts to look like this (with different IPs and hostnames of course)
Code:
127.0.0.1       localhost.localdomain   localhost
192.168.0.100   server1.example.com     server1
# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts
I'm curious about that second line. I know it'll be my actual server ip, but what does it specify? what is the 'server1' at the end of the line specifying? I *think* that 'server1' would be part of my bash prompt when i login, but am not sure. Is it used for anything else?
 
Old 07-02-2010, 04:49 PM   #2
pljvaldez
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Basically the names specified are the hostnames of the machine. You should typically specify the fully qualified domain name and the local host name (what is at the bash prompt). Note that you can assign more than one hostname to a particular IP address. This is how I cheat on some windows computers to block certain domains. I just redirect undesired sites to localhost (127.0.0.1). Of course, it's easy enough to change, but frustrates the kids since they don't know what I did.

If you haven't blundered across it yet, www.aboutdebian.com is a good beginning debian server site.
 
Old 07-02-2010, 04:49 PM   #3
Dinithion
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server1 is just an alias for server1.example.com

Your computer checks /etc/hosts before doing an DNS-lookup on a domain. If it finds an entry in /etc/hosts, it uses it. f.eks. 'ping server1' would be the same as 'ping server1.example.com' and the same as 'ping 192.168.0.100'. Well, not the same in that sense, but it would ping the same computer

Edit:
/etc/hosts also has a historical background. In the old-days, before there were DNS-servers, this hosts file could be downloaded so you didn't have to use IP-addresses, but could use domains instead. After a while, it was inconvenient to use hosts due to updates and changes, and therefor they made a DNS-service.

Last edited by Dinithion; 07-02-2010 at 04:52 PM.
 
Old 07-02-2010, 04:51 PM   #4
harry edwards
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See http://www.faqs.org/docs/securing/chap9sec95.html

Last edited by harry edwards; 07-02-2010 at 04:59 PM.
 
Old 07-02-2010, 06:17 PM   #5
yesyayen
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/etc/hosts file contains data in this order,

IP-addr hostname alias

here server1 is alias name for server1.example.com(FQDN)
 
Old 07-02-2010, 08:26 PM   #6
paulsm4
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Hi -

As the previous posters said, the entries in "/etc/hosts" are just aliases for mapping IP addresses to a meaningful name.

One of these aliases is your "hostname" (and you can screw things up royally if you put in the WRONG IP address here) ...

... but /etc/hosts is NOT the place where you actually ASSIGN your PC's hostname. And that "assigned" hostname is the one in your prompt:

http://www.debian-administration.org...tworking_setup

'Hope that helps .. PSM
 
  


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