RE: [squid-users] DNS cache-only server question

Why don't you setup squid to accelerate those sites, and then use a
redirector to write the host header to your hearts desire.

Rob

> -----Original Message-----
> From: Pablo Sanchez [mailto:pablo@purecarbon.com]
> Sent: Wednesday, September 19, 2001 2:01 PM
> To: squid-users@squid-cache.org
> Subject: RE: [squid-users] DNS cache-only server question
>
>
> I understand what you're saying but I don't believe some of your
> points are 100% correct. I'm not trying to bite the gift horse in the
> mouth mind you. :)
>
> I did an 'strace' on ping to see what it's doing. I can see that it's
> also 'talking' to port 53 as is SQUID.
>
> In the SQUID ../lib/rfc1035.c library, I see that we call
> 'rfc1035BuildAQuery' when given a supposed FQDN. Uncommenting the
> 'main' I'm able to replicate my 'problem'
>
> I believe if I can pass the same flags that 'ping' is passing to
> named, I should be able to 'hack' the underlying routine to get what I
> need done.
>
> So why do I need this done? I realize that it's an RFC violation but
> the RFC didn't consider the situation where I'm in a test environment.
> Basically, our application is a web app with an apache web server. It
> answers to CNAME'd values for our different customers and presents
> them with a different 'look' based on these DNS values. We're in the
> middle of QA (yes, amazing that s/w companies still do this! :), and
> I need to run through some of our QA sites.
>
> For instance:
>
> qa-one.foobar.com -> look 'n feel #1
> qa-one.foobar.com -> look 'n feel #2
>
> My problem is that I'm using StarBand now that my ISP kicked its heals
> up. StarBand has a proxy server too and it rightly insists FQDN's as
> does SQUID. However, I need to test (even though I don't want to, but
> that's another story isn't it? :) so I need to 'fake' out SQUID.
>
> Prior to this, I had DSL and was able to get everything working.
>
> I'm not a purist per say, just need to get my work done and am falling
> behind.
>
> I think what you propose will work but I'm thinking of worst case
> hacking rfc1035.c to inspect /etc/hosts for values before going to
> named. Best case, I can check out ping's source code and see what it
> sends to named.
>
> Hope that helps.
> ---
> Pablo Sanchez mailto:pablo@purecarbon.com
> Ph : 303.939.8897 Fax: 603.720.7723
> Cell: 303.717.5889
>
> > -----Original Message-----
> > From: Colin Campbell [mailto:sgcccdc@citec.qld.gov.au]
> > Sent: Tuesday, September 18, 2001 9:41 PM
> > To: Pablo Sanchez
> > Cc: squid-users@squid-cache.org
> > Subject: RE: [squid-users] DNS cache-only server question
> >
> >
> > Hi,
> >
> > I'm starting to get confused. Exactly what are you trying
> > to achieve?
> > Before you answer that though, what you must understand is that when
> > you define a CNAME you do so in the domain for which the file is the
> > authoritative data. So, when you have, for example
> >
> > named.conf:
> >
> > zone "hairball.com" {
> > file "db.hairball";
> > type master;
> > }
> >
> > db.hairball:
> >
> > ...
> > qa-one.foobar.com IN CNAME web2.hairball.com.
> >
> > you are defining qa-one.foobar.com.hairball.com. You are
> > NOT defining
> > qa-one.foobar.com. When you use ping, it asks the DNS for the IP for
> > qa-one.foobar.com.hairball.com. That's because it calls
> > gethostbyname()
> > which (possibly after consulting some resolution
> > configuration switch
> > file) will ask the DNS for the FQDN
> > (qa-one.foobar.com.hairball.com) which
> > your DNS as you have configured it, knows about. gethostbyname() is
> > designed to be "user friendly" and calls the resolver
> > routine res_search()
> > which will read and parse /etc/resolv.conf looking for "domain" or
> > "search" directives and applying the returned domain(s),
> > modifying the
> > search at each go until it either gets an answer or fails.
> > This can be a
> > very time consuming operation, taking 10-15 seconds which
> > is far too long
> > for something like squid. Consequently squid doesn't call
> > gethostbyname()
> > and doesn't even call res_search(). It goes straight to
> > res_query() which
> > (in theory) will be very much quicker. If you have squid
> > configured to not
> > add the local domain to unqualified names, you'll find that
> > squid cannot
> > find "web2". It will find "web2.hairball.com" because your
> > DNS knows about
> > it. To squid, "web2" is not "web2.hairball.com.", it's
> > "web2" in the root
> > domain, ie "web2.".
> >
> > So getting back to your problem. If you want squid to turn
> > qa-one.foobar.com into web2.hairball.com you'll need to
> > have your DNS
> > configured as follows:
> >
> > named.conf
> >
> > zone "hairball.com" {
> > file "db.hairball";
> > type master;
> > };
> >
> > zone "foobar.com" {
> > file "db.foobar";
> > type master;
> > };
> >
> > db.hairball:
> >
> > web2 IN A 10.9.8.7
> >
> > db.foobar:
> >
> > qa-one.foobar.com IN CNAME web2.hairball.com.
> >
> > That is it. There is no other way. Repeat after me, there
> > is no other way.
> > Where this will get you into trouble, though, is if you
> > want "foobar.com"
> > to refer to a real domain. Then what I have told you to do
> > is going to
> > make the real domain effectively inaccessible. In this case
> > you probably
> > want to use a redirector that will selectively rewrite
> > URLs. Then you
> > could have your redirector get a URL like
> >
> > http://qa-one.foobar.com/index.html
> >
> > and rewrite it to be
> >
> > http://web2.hairball.com/index.html
> >
> > which achieves the same result. The nice thing about doing
> > it this way is
> > that you can have your redirector "consult outside
> > influences" and alter
> > its behaviour according to those influences. For example,
> > you could have
> > the redirector check the status of your link. If it's up,
> > go to the real
> > site (ie don't rewrite the URL) but if it's down, go
> > somewhere else (eg
> > web2.hairball.com).
> >
> > Are we getting closer? :-)
> >
> > On Tue, 18 Sep 2001, Pablo Sanchez wrote:
> >
> > > Before I continue down that path a bit more... shouldn't it be
> > > possible to have SQUID talk to named much like 'ping?'
> > In my simple
> > > pea-like brain, I'm thinking if SQUID didn't make it
> > mandatory to have
> > > FQDN's, I'd be set.
> >
> > Colin
> >
> >
>
>
Received on Tue Sep 18 2001 - 22:02:54 MDT