I understand the possible issues with round-robin DNS and load
balancers. However, it doesn't appear that ads.bfast.com is using
round-robin. Of course, there's no telling if they're using other
load-balancing solutions.
I guess my question boils down to this: if LWP and Netscape
Navigator are able to retrieve the URL, what are they doing to get
the graphic that I'm not doing when I manually telnet to port 80
to issue the HTTP request?
I think I just answered my own question. Using the -U option for
lwp-request, I see that the GET request is formed a bit differently
than I've always done it:
GET http://ads.bfast.com/clients/etoys/dot_clear.gif
Host: ads.bfast.com
User-Agent: lwp-request/1.32
I guess this server won't respond to a request unless to URL starts
with http://ads.bfast.com. Looks like Oracle_Web_listener is another
brain-dead server. Frankly, I'm surprised that Navigator would be
able to retrieve this document, since I'm pretty sure that it doesn't
form its HTTP requests this way.
Very strange... thanks for all the suggestions!
Jason Priebe
WRAL OnLine
http://www.wral-tv.com/
> -----Original Message-----
> From: Ask Bjoern Hansen [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, January 04, 2000 8:06 PM
> To: Marvin Simkin
> Cc: priebe%wral-tv.com; libwww%perl.org
> Subject: Re: Strange server response
>
>
> On 30 Dec 1999, Marvin Simkin wrote:
>
> [...]
> > Also big sites sometimes have several servers responding to
> one hostname, and
> > maybe one server doesn't have a complete content set. If
> your clients cache IP
> > addresses (or query different DNS servers) one client could
> consistently be
> > connecting to the good server while another doesn't. This
> seems unlikely, but
> > conceivable. Maybe you could test this by using a raw IP
> address instead of
> > hostname.
>
> Very often the "real" servers will be well hidden behind some
> loadbalancer
> in a scheme like that. It seems pretty ... uhmn.. unclever to
> put simple
> content that is meant to be cached on a "Oracle_Web_listener"
> server and
> not something efficient.
>
> now it works for me too btw:
>
> [ask@impatience ask]$ lwp-request -d -S
> http://ads.bfast.com/clients/etoys/dot_clear.gif
> GET http://ads.bfast.com/clients/etoys/dot_clear.gif --> 200 OK
>
> I guess some ad networks are just more reliable than others. ;-)
>
>
> - ask
>
> --
> ask bjoern hansen - <http://www.netcetera.dk/~ask/>
> more than 60M impressions per day, <http://valueclick.com>
>
