A Backup Server ?

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    I've just acquired a used Dell Optiplex 280 for use as a backup Apache
Server (It has Win XP Pro (sp3) as does my main Apache Server, and my dev

    This new machine has the latest Apache Server (2.2.17). The main apache
server has version 2.2.10)

    They're now all on a Dlink Dl-740P router.

    What is the easiest way to 'flick' back and forth between the two
servers to test and ensure that I can quickly go to the backup server and
return to the main server with a minimum of fuss, and so clients will not be
affected ?


Mel Smith

Re: A Backup Server ?

On 02/02/2011 10:35 AM, Mel Smith wrote:
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  I am not clear what you mean here. It would seem precarious to have
all the equipment stacked on the router like that.

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  If you haven't already, create an DNS alias in your name server for
the target HTTP server. To switch between servers, change the alias
value as desired.

James Moe
jmm-list at sohnen-moe dot com

Re: A Backup Server ?

James said:
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    I have CoxCable coming into my router, then out from the router I have
my 1.-development machine, 2.-Main ApacheServer (an older Dell), and now
3.-a 'newer' used Dell (i.e., only four years old) as a prospective backup
Apache Server

    The fourth output is to my roku video player for streaming Netflix
movies --- its a busy router !
    and btw, what is a better, faster, wired router that I should buy ??)

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    My name server is with www.zoneedit.com, andI'll have to puzzle on what
you said.

    On thinking this over, I think I can answer my own question:

        If I just change the port assignment in my router software, from say
102 to 117, maybe that will work ??

Thanks for your response.


Re: A Backup Server ?

On 2/2/2011 2:52 PM, Mel Smith wrote:
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I like my

Linksys E3000

It's both wired and wireless (dual band). It looks pretty sleek too! But
it isn't cheap (I believe around $150 now).

It may or may not do exactly what you want, you'll have to look at its
features and specs. But it works quite well for me with:

2 Win7 Home Premium 64-bit laptops - wireless (N band)
2 Win7 Professional 64-bit desktops - wired Gigabit LAN
1 WinXP Professional 32-bit desktop - wireless (N band)
1 WinXP Home Edition 32-bit desktop - wireless (N band)
1 Seagate Expansion External SATA Hard Drive - wired via USB
1 Sony Bravia LCD 1080p HDTV - wired (N band)
1 Sony Blu-Ray Home Theatre System - wireless (N band)
1 Nineteno Wii Game Console - wireless (G band)

My Win7 Pro and XP Pro desktops both have IIS servers running for my
local web developing prior to deployment;  bot are accessible from all
desktops and laptops plus the virtual WinXP Mode on my Win7 Pro desktop
and Win98Se and Vista Business (32-bit) on my WinXP Pro desktop in
Microsoft Virtual PC 2007.

I guess my router sometimes gets "fairly" busy. My wife and I will be
streaming a Netflix movie to the home theatre while we're both using our
laptops accessing the Internet, and I'll have a remote connection to my
desktop via Live Mesh plus our grandson will be playing an online RPG game.

BTW, YES, updates are fun as I do not have them on auto as I want to
choose what and when are updated.

To reply remove SPAM NOT

Re: A Backup Server ?

Chet said:

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    I'll take a look at that router.

    Thanks for the recommendation !


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    Wow, and I thought *my* old router was busy !!


Re: A Backup Server ?

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Changing the IP address via DNS is slow, and the change can take many hours
to propogate. Changing the ports at your router is instantaneous. Neither
will affect your clients provided they don't use the sane dns-name/ports as
you are using for testing.
 Brian Cryer

Re: A Backup Server ?

Brian said:
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    O.K., that's what I'll do for now.  When I get a new, better, faster,
router (say, the Cisco E3000 wired/wireless one), I assume that *it* will
allow the same instanteous changes too ??

    btw,  as an example (zoneedit changes my web address from
www.mesaeastpark.com to ww2.mesaeastpark.com:4296 -- so I guess there would
not be any problem.


-Mel Smith

Re: A Backup Server ?

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However fast your router is it won't help with how quickly DNS takes to

The problem is that when someone does a DNS lookup the results of that
lookup are likely to be cached anywhere between (and including) that local
PC and the DNS servers. So if you change the entry at the DNS server that
won't affect anywhere where that has been cached.

So, lets say you have two users who want to get to your site. User 1
connects, something happens and you need to change the IP address of the
site. User 1 still has the old IP address and won't get the new one until
the copy he has times-out and all the intermediary caches of that IP address
expire. So it could be the following day before user 1 sees your new IP
address and can connect again. User 2 however doesn't try connecting to your
site until after you'd changed the IP address and the IP address isn't
cached anywhere between his PC and your DNS servers, so user 2 picks up your
new ip address and isn't aware that you needed to change it.

If you are working on a LAN with a local DNS server then you can expediate
this by flushing the cache on your local PC thus forcing it to go back to
the DNS server for the new IP address.

This is why changs to IP addresses can take up to 24 hours (or whatever) and
yet some people still manage to pick up the change immediately.

If on the other hand you are chaning the port assignment then (assuming)
that is done at your router, then it affects everyone straight away because
there is no caching involved.

Hope this helps.
 Brian Cryer

Re: A Backup Server ?

On 02/03/2011 02:52 AM, Brian Cryer wrote:
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  Not if there is a local DNS server; the change is immediate. I would
presume so since he has his own HTTP servers and multiple hosts.

James Moe
jmm-list at sohnen-moe dot com

Re: A Backup Server ?

On 2/4/2011 2:17 AM, James Moe wrote:
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Incorrect.  He's already said he's using zoneedit.com.  When he changes
the ip address there, that change must be propagated to the primary name
servers, then to the secondary name servers, and on down to the name
server he's using.  Brian is correct that this change can take many
hours to propagate.

And if it were a local DNS server, the change wouldn't be seen by the
rest of the world.

Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.

Re: A Backup Server ?

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I run a DNS server on my network at work. If I change an IP address I still
need to flush the local cache on my PC otherwise it won't even ask the DNS
server for the IP. So, no the change isn't immediate - or at least to
qualify, if the IP address has already been requested then where it might be
cached the change won't take effect immediatly but where it hasn't been
cached then it will.
 Brian Cryer

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