[PLUG] what IP does a web page come from

Carla Schroder carla at bratgrrl.com
Sat Sep 27 19:01:01 UTC 2003


On Saturday 27 September 2003 6:22 pm, Ed Sawicki wrote:
> Re: [PLUG] what IP does a web page come from
> From: Ed Sawicki <ed at alcpress.com>
> To: plug at lists.pdxlinux.org
>
> On Sat, 2003-09-27 at 17:53, Brent Rieck wrote:
> > Carla Schroder wrote:
> > > How do you tell what server a particular Web page is from? Let's say
> > > the identical page is on two different servers, on two different
> > > networks- how do you know which one? (No, you cannot change one, it is
> > > not under your control)
> >
> > Can't you just do:
> >    host <the part between the "http://" and the next "/">
> >
> > or am I misunderstanding your question?

>
> When I replied to Carla, I assumed that the Web servers would have
> different IP addresses - that we weren't talking about a cluster
> of servers all with the same IP apparent address. If my assumption
> is correct, asking DNS for the address would yield two or more
> answers and she wouldn't know which one.

Right. Doing any of the usual lookups- dig, host, nslookup- do not trace the 
origin of a specific page. I was futzing around with some domains hosted at 
different providers, and got sidetracked because each one uses the identical 
Apache Test page:

69.57.134.33  <-- new web host, citadelhost
207.218.248.34  <-- old web host, Page-zone

The Apache Test page displays when you enter the URL of a domain hosted on 
their server, but DNS is not caught up yet, for whatever reason. What would 
be lovely is each site putting some kind of identification on their default 
Apache pages. (I asked already)

For those who like to fool around with this kind of thing, try 
www.mtgadvocates.com and mtgadvocates.com. You'll either get the site, or an 
Apache Test page. There are a lot of chefs in this DNS kitchen: 
Easystreet.com manages their DNS. The site is hosted at Citadelhost.com. 
Easystreet configured them so:

;; ANSWER SECTION:
www.mtgadvocates.com.   77810   IN      CNAME   mtgadvocates.com.
mtgadvocates.com.       77813   IN      A       69.57.134.33
mtgadvocates.com.       77813   IN      A       69.57.134.153
;; AUTHORITY SECTION:
mtgadvocates.com.       77813   IN      NS      dns3.easystreet.com.
mtgadvocates.com.       77813   IN      NS      dns1.easystreet.com.
mtgadvocates.com.       77813   IN      NS      dns2.easystreet.com.


Querying both the Citadelhost nameservers looks like this:

69.57.134.33 
;; ANSWER SECTION:
www.mtgadvocates.com.   14400   IN      CNAME   mtgadvocates.com.
mtgadvocates.com.       14400   IN      A       69.57.134.33

;; AUTHORITY SECTION:
mtgadvocates.com.       14400   IN      NS      ns5.xfwm.com.
mtgadvocates.com.       14400   IN      NS      ns6.xfwm.com.

69.57.134.153
;; ANSWER SECTION:
www.mtgadvocates.com.   14400   IN      CNAME   mtgadvocates.com.
mtgadvocates.com.       14400   IN      A       69.57.134.33

;; AUTHORITY SECTION:
mtgadvocates.com.       14400   IN      NS      ns6.xfwm.com.
mtgadvocates.com.       14400   IN      NS      ns5.xfwm.com.

It wouldn't even be all that interesting, except the old host I moved 
mtgadvocates.com away from uses the exact same Apache Test page. So I got to 
wondering about how in the heck to know which one I was hitting? (I assume 
that once DNS propagation takes place (the DNS was changed yesterday) that 
ole test page won't come back. )

So that is how I waste^H^H^H^H gainfully spent my Saturday.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~
Carla Schroder
www.tuxcomputing.com
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~~~~~~~~~~~~~~~~~~~~~~~~~





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