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If yes, could you guys advise how to do it?

thanks
Richard

Richard TU wrote:

> If yes, could you guys advise how to do it?

1. Install two NICs.

2. Create configurations for the NICs with different IP addresses. That is
the normal configuration anyway.

3. Make entries into /etc/hosts that map different host names to the IP
addresses.

But this suggestion will not work in all ways. Logging onto the server and
issuing --

$ hostname

-- will not produce two hostnames, depending on which NIC you have accessed
the system by.

Why not simply state the problem, not your idea of a solution?

--
Paul Lutus
http://www.arachnoid.com

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Richard TU wrote:
> If yes, could you guys advise how to do it?

Yes, a linux system can have two host names and two IP addresses. Most already do.

For hostnames, you have to determine what sort of hostname you are interested in.

- - If it is the name returned by the hostname(1) utility, then you only get one
name. Sorry.
- - If it is the name used by Samba as your systemname within a workgroup or
domain, then again, you only get one. Sorry.
- - However, if it is the name associated to your IP address, then you get as
many names as you can assign to your IP address. You can use the /etc/hosts
file (see hosts(5)) to assign as many names as you want to your static IP
addresses. You can also use your DNS server to assign the names. You already
have at least /one/ host name for your system: IP address 127.0.0.1 is, by
convention, named as "localhost" (or "localhost.localnet") by the /etc/hosts
file.

As for IP addresses, if your system is connected to a network, then it already
has at least two IP addresses. Run the ifconfig(8) command, and it will list
each interface you have. Most interfaces will be assigned an IP address,
including the "lo" interface (which is assigned the IP address 127.0.0.1). You
get as many IP addresses as you have network interfaces for. (And, btw, each
IP address can have a host name, assigned either through /etc/hosts or through
DNS; you already have the hostname of "localhost" assigned this way, for
instance.)

To get more than one working /network/ IP address, you have to have more than
one working network adaptor. You either install multiple NICs into your
system, or you use Linux "logical" networking interface. This permits you to
have (for instance) an eth0 /and/ an eth0:0 device; two logical interfaces
each with it's own IP address, but on one physical NIC. See the ifconfig(8)
manual page for details.

- --
Lew Pitcher

Master Codewright & JOAT-in-training | GPG public key available on request
Registered Linux User #112576 (http://counter.li.org/)
Slackware - Because I know what I'm doing.
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Paul Lutus wrote:

>Richard TU wrote:
>
>
>
>>If yes, could you guys advise how to do it?
>>
>>
>
>1. Install two NICs.
>
>
1) You can have multiple IP addresses bound to a single NIC. You only
need different NIC's if you are going to hook them physically to
different networks.
2) You can have multiple names for a machine, even when they point to
the same IP address. I do this all the time in order to call machines
by their roll name. This allows me to change what servers handle
various requests by just changing the IP address for the name in the
DNS. Here are some examples:
ns.domain.com -> main name server for the domain
mail.domain.com -> main mail exhanger for the domain
fileserver.domain.com -> main file server for the domain

etc..

Of courese, as others have stated, typing hostname will only give you
the primary hostname, and looking up the name via an IP address will
generally only return the primary hostname.

Cliff

--
_____cliff_rayman_____cliff_@_rayman_._com_____

Lew Pitcher wrote:

> Yes, a linux system can have two host names and two IP addresses.
Most already do.
>
> For hostnames, you have to determine what sort of hostname you are
interested in.

>
> - - If it is the name returned by the hostname(1) utility, then you
only get one
> name. Sorry.
At least with the stock kernel. There is the vserver patch which, among
others, can assign different hostnames for every context. I doubt the
original poster is interested in it, but there IS a way.

> - - If it is the name used by Samba as your systemname within a
workgroup or
> domain, then again, you only get one. Sorry.
That is a lot simpler, you can have multiple Samba installs, bound to
different network interfaces. Each one can have their own hostname.

There ARE some things you can't do in Linux, but these are not among
them

--
Petre.

Richard TU wrote:
> If yes, could you guys advise how to do it?
>
I see most people assume you mean one thing by a Linux box. And they
probably assume correctly what you mean.

But there is another way of looking at things.

When I have a dual boot machine (e.g., Linux and Windows), I give it a
different but similar IP address. E.g. 192.168.100.1 for Windows and
192.168.100.101 for Linux.

Then my other machines on the LAN can impose stricter requirements on the
Windows box and the Linux box, even if we are talking about the same box,
just one with different OS running at the time -- which is different from
my point of view.

So my main machine, the one connected to the Internet directly, perceives
two machines out on the LAN, a Windows machine and a Linux machine, even
though there is only one box there. It might make inferences from the fact
that only one is active at a time, but that is about it.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 08:30:00 up 8 days, 19:34, 3 users, load average: 4.30, 4.22, 4.19

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Ratiu Petru wrote:
> Lew Pitcher wrote:
>
>
>>Yes, a linux system can have two host names and two IP addresses.
>
> Most already do.
>
>>For hostnames, you have to determine what sort of hostname you are
>
> interested in.
>
>
>>- - If it is the name returned by the hostname(1) utility, then you
>
> only get one
>
>> name. Sorry.
>
> At least with the stock kernel. There is the vserver patch which, among
> others, can assign different hostnames for every context. I doubt the
> original poster is interested in it, but there IS a way.

I did not know that. Thanks for the info.

>
>>- - If it is the name used by Samba as your systemname within a
>
> workgroup or
>
>> domain, then again, you only get one. Sorry.
>
> That is a lot simpler, you can have multiple Samba installs, bound to
> different network interfaces. Each one can have their own hostname.

Aha! That's the key; they have to be bound to different interfaces.
Again, I did not know that. Thanks again

> There ARE some things you can't do in Linux, but these are not among
> them
>

The thing I find with Linux is that there's always more to learn. I
/love/ this OS. <grin>

- --

Lew Pitcher, IT Consultant, Enterprise Data Systems
Enterprise Technology Solutions, TD Bank Financial Group

(Opinions expressed here are my own, not my employer's)
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Thanks a lot for your replies.
I understand a lot now after you explained it.

Here is my problem:
I have two linux boxes, each with its own IP and hostname. Now I want to
combine these two into one linux box, but still keep the two sets of IP
addresses and hostnames. For example, when I go to the web page, both
hostnames should lead me to the same linux box after the combination.
I prefer to use one NIC to listen to two IP addresses like setting eth0 and
eth0:0 to different IP address. What I have to do is to add the hostname in
the hosts file, is that right?

thanks
Richard

"Lew Pitcher" <lpitcher@sympatico.ca> wrote in message
news:1r17d.28494$tT2.1526581@news20.bellglobal.com ...
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Richard TU wrote:
> > If yes, could you guys advise how to do it?
>
> Yes, a linux system can have two host names and two IP addresses. Most
already do.
>
> For hostnames, you have to determine what sort of hostname you are
interested in.
>
> - - If it is the name returned by the hostname(1) utility, then you only
get one
> name. Sorry.
> - - If it is the name used by Samba as your systemname within a workgroup
or
> domain, then again, you only get one. Sorry.
> - - However, if it is the name associated to your IP address, then you get
as
> many names as you can assign to your IP address. You can use the
/etc/hosts
> file (see hosts(5)) to assign as many names as you want to your static
IP
> addresses. You can also use your DNS server to assign the names. You
already
> have at least /one/ host name for your system: IP address 127.0.0.1 is,
by
> convention, named as "localhost" (or "localhost.localnet") by the
/etc/hosts
> file.
>
> As for IP addresses, if your system is connected to a network, then it
already
> has at least two IP addresses. Run the ifconfig(8) command, and it will
list
> each interface you have. Most interfaces will be assigned an IP address,
> including the "lo" interface (which is assigned the IP address 127.0.0.1).
You
> get as many IP addresses as you have network interfaces for. (And, btw,
each
> IP address can have a host name, assigned either through /etc/hosts or
through
> DNS; you already have the hostname of "localhost" assigned this way, for
> instance.)
>
> To get more than one working /network/ IP address, you have to have more
than
> one working network adaptor. You either install multiple NICs into your
> system, or you use Linux "logical" networking interface. This permits you
to
> have (for instance) an eth0 /and/ an eth0:0 device; two logical interfaces
> each with it's own IP address, but on one physical NIC. See the
ifconfig(8)
> manual page for details.
>
> - --
> Lew Pitcher
>
> Master Codewright & JOAT-in-training | GPG public key available on request
> Registered Linux User #112576 (http://counter.li.org/)
> Slackware - Because I know what I'm doing.
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Richard TU wrote:
> Thanks a lot for your replies.
> I understand a lot now after you explained it.
>
> Here is my problem:
> I have two linux boxes, each with its own IP and hostname. Now I want to
> combine these two into one linux box, but still keep the two sets of IP
> addresses and hostnames. For example, when I go to the web page, both
> hostnames should lead me to the same linux box after the combination.
> I prefer to use one NIC to listen to two IP addresses like setting eth0 and
> eth0:0 to different IP address. What I have to do is to add the hostname in
> the hosts file, is that right?

Remember that /etc/hosts only affects the system on which it resides.
So, each system that will access the new 'combined' system will need
corresponding changes to its own /etc/hosts file.

If you don't have control over these outside systems, then you should
make a change at the DNS level.


Assuming (for the purposes of this illustration) that your two sites are
currently named foo.bar.com (at IP address 10.0.0.1) and rosanne.bar.com
(at 10.0.0.2) here's what I would do with the combined system...

In your network config scripts
ifconfig eth0 10.0.0.1 broadcast 10.255.255.255 netmask 255.0.0.0
ifconfig eth0:0 10.0.0.2 broadcast 10.255.255.255 netmask 255.0.0.0

In your various /etc/hosts file
10.0.0.1 foo.bar.com foo
10.0.0.2 rosanne.bar.com rosanne
(alternatly, update your DNS to point these domain names to the proper
IP addresses).

In your Apache httpd.conf file
<VirtualHost foo.bar.com>
ServerAdmin webmaster@foo.bar.com
DocumentRoot /var/www/foo.bar.com
ServerName foo.bar.com
ErrorLog logs/foo.bar.com-error_log
CustomLog logs/foo.bar.com-access_log common
</VirtualHost>
<VirtualHost rosanne.bar.com>
ServerAdmin webmaster@rosanne.bar.com
DocumentRoot /var/www/rosanne.bar.com
ServerName foo.bar.com
ErrorLog logs/rosanne.bar.com-error_log
CustomLog logs/rosanne.bar.com-access_log common
</VirtualHost>

In directory /var/www/foo.bar.com
place the web pages for web domain foo.bar.com

In directory /var/www/rosanne.bar.com
place the web pages for the web domain rosanne.bar.com




- --

Lew Pitcher, IT Consultant, Enterprise Data Systems
Enterprise Technology Solutions, TD Bank Financial Group

(Opinions expressed here are my own, not my employer's)
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Lew Pitcher wrote:
[snip]

Correction... See below

> In your Apache httpd.conf file
> <VirtualHost foo.bar.com>
> ServerAdmin webmaster@foo.bar.com
> DocumentRoot /var/www/foo.bar.com
> ServerName foo.bar.com
> ErrorLog logs/foo.bar.com-error_log
> CustomLog logs/foo.bar.com-access_log common
> </VirtualHost>
> <VirtualHost rosanne.bar.com>
> ServerAdmin webmaster@rosanne.bar.com
> DocumentRoot /var/www/rosanne.bar.com
ServerName rosanne.bar.com
> ErrorLog logs/rosanne.bar.com-error_log
> CustomLog logs/rosanne.bar.com-access_log common
> </VirtualHost>
>
> In directory /var/www/foo.bar.com
> place the web pages for web domain foo.bar.com
>
> In directory /var/www/rosanne.bar.com
> place the web pages for the web domain rosanne.bar.com

- --

Lew Pitcher, IT Consultant, Enterprise Data Systems
Enterprise Technology Solutions, TD Bank Financial Group

(Opinions expressed here are my own, not my employer's)
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