IPs- and FDQNs on localhost with subnets on MINT 17.3?

Leoncito · 08-09-2017, 09:43 AM

Hi,

I am searching how to setup certain IPs (IPv4) with two (or more) subnets on my localhost for testing and (still) not using virtual machines.
I have a Laptop which I am carrying around all the time traveling and I wonder how it is possible to set such an environment up for testing purposes; e.g. later a test and learning of a bacula, postfix, alfresco or a private CA-SSL, all based on the IPs and FDQNs.

I would like to set up a private subnet (class A).

I am still a bit confused how I map a domain on which IP and how I map two domains on one IP.

Could you suggest how I make it going?

Thank you.

Leoncito

ShadowCat8 · 08-14-2017, 08:40 PM

Greetings,

It sounds like there is some confusion about IPs versus hosts (e.g. Fully-Qualified Domain Names).

IP addresses are what is assigned to a network interface to designate where the system is on the network and where to address it for connections. The FQDN is the product of DNS translating the IP address to a name that should be easier for folks to remember. The translation between the FQDN and the IP address is done by DNS, or you can use your system's "/etc/hosts" file to accomplish the same thing.

A base, default "/etc/hosts" file should look something like this:

Code:

# /etc/hosts: Local Host Database
#
# This file describes a number of aliases-to-address mappings for the for 
# local hosts that share this file.
#
# In the presence of the domain name service or NIS, this file may not be 
# consulted at all; see /etc/{host,nsswitch}.conf for the resolution order.
#

# IPv4 and IPv6 localhost aliases
127.0.0.1       localhost
::1             localhost

#
# Imaginary network.
#10.0.0.2               myname
#10.0.0.3               myfriend
#
# According to RFC 1918, you can use the following IP networks for private 
# nets which will never be connected to the Internet:
#
#       10.0.0.0        -   10.255.255.255
#       172.16.0.0      -   172.31.255.255
#       192.168.0.0     -   192.168.255.255
#
# In case you want to be able to connect directly to the Internet (i.e. not 
# behind a NAT, ADSL router, etc...), you need real official assigned 
# numbers.  Do not try to invent your own network numbers but instead get one 
# from your network provider (if any) or from your regional registry (ARIN, 
# APNIC, LACNIC, RIPE NCC, or AfriNIC.)
#

... and when you want to configure your system to know itself on it's "home" network, you change it to something like this (assuming the IP address on the home network is 192.168.1.101.):

Code:

#

# IPv4 and IPv6 localhost aliases
127.0.0.1       localhost
::1             localhost

192.168.1.101   mycomp.home-domain.com mycomp

Now, you are going to take your system into work and put it on the network there, which will assign it a 10.10.17.58 IP address, so now you should update your '/etc/hosts' file to look something like this:

Code:

#

# IPv4 and IPv6 localhost aliases
127.0.0.1       localhost
::1             localhost

192.168.1.101   mycomp.home-domain.com mycomp
10.10.17.58     mycomp.work-domain.com

You can read more about the "/etc/hosts" file at this LQ Wiki page.

HTH. Let us know.

Habitual · 08-15-2017, 06:49 AM

Clearly cited examples:
in a terminal issue:

Code:

man hosts  | less -Ip '^EXAMPLE'

If "Fred" wants to call the mailserver "mailserver", fine, adjust Fred's /etc/hosts on his system

Code:

10.1.100.10    mailserver.domain.com       mailserver

If "Mike" wants to get to the mailserver using zimbrahost, adjust his Mike's /etc/hosts on his system

Code:

10.1.100.10    mailserver.domain.com      zimbrahost

The names are completely arbitrary.

Have fun!

Leoncito · 08-15-2017, 09:04 AM

Hi,

thank you @shadowcat8 and @habitual! That helped me out at the current stage with my issue.

All the best

Leoncito