[vox-tech] Tracking down a "redirect"

Wed Jun 14 16:20:43 PDT 2006

On Wed, Jun 14, 2006 at 03:57:25PM -0700, Mark K. Kim wrote:
> On Wed, Jun 14, 2006 at 03:16:50PM -0700, Micah J. Cowan wrote:
> > On Wed, Jun 14, 2006 at 02:30:54PM -0700, Richard Crawford wrote:
> [snip]
> > > Domain http://unexdlc.ucdavis.edu should be resolving to IP address 
> > > 152.79.198.9.  However, it is instead resolving to http://extensiondlc.net, 
> > > which is an entirely different IP address.  Similarly, typing 
> > > http://152.79.198.9 into a browser brings up extensiondlc.net, which should 
> > > not be happening.
> [snip]
> > You say "... should be resolving to IP address 152.79.198.9." However,
> > according to dig:
> [snip]
> >     unexdlc.ucdavis.edu.    7200    IN      CNAME   extensiondlc.net.
> >     extensiondlc.net.       86364   IN      A       204.11.233.24
> 
> Furthermore, connecting directly to 152.79.198.9 causes "301 Moved
> Permanently" redirection to unexdlc.ucdavis.edu, which is an alias for
> extensiondlc.net.  So it appears to be a 2-layer problem - DNS as well
> as some server issue.

<snip>

> 152.79.198.9.  FYI, if you try HTTP/1.1 with host set to
> unexdlc.ucdavis.edu:
> 
>   $telnet 152.79.198.9 80
>   Trying 152.79.198.9...
>   Connected to 152.79.198.9.
>   Escape character is '^]'.
>   GET / HTTP/1.1
>   host: unexdlc.ucdavis.edu
>   
>   HTTP/1.1 302 Found
>   Date: Wed, 14 Jun 2006 22:52:50 GMT
>   Server: Apache/2.0.44 (Unix) mod_perl/1.99_08 Perl/v5.8.0 DAV/2
>   Location: http://unexdlc.ucdavis.edu/cfmx/DLC/
>   Content-Length: 340
>   Content-Type: text/html; charset=iso-8859-1
>   
>   <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
>   <html><head>
>   <title>302 Found</title>
>   </head><body>
>   <h1>Found</h1>
>   <p>The document has moved <a
>   href="http://unexdlc.ucdavis.edu/cfmx/DLC/">here</a>.</p>
>   <hr />
>   <address>Apache/2.0.44 (Unix) mod_perl/1.99_08 Perl/v5.8.0 DAV/2 Server
>   at unexdlc.ucdavis.edu Port 80</address>
>   </body></html>
>   
>   Connection closed by foreign host.
> 
> It's a "302 Found" but it tells you to go to unexdlc.ucdavis.edu which
> is an alias for extensiondlc.net.  However you look at it, you're being
> sent to extensiondlc.net.

Well, but the server doesn't necessarily understand that
unexdlc.ucdavis.edu is a separate host: You've just told it (via the
Host header) that /it/ is unexdlc... so it probably thinks its
redirecting you to a different path on the same directory.

...huh. That's funny: I don't get the redirect message when /I/
connect... I get a 200 OK with an html body.

traceroute to 152.79.198.9 (152.79.198.9), 30 hops max, 40 byte packets
1  192.168.1.2 (192.168.1.2)  0.414 ms  0.311 ms  0.258 ms
2  69.36.252.1 (69.36.252.1)  1.309 ms  1.383 ms  1.207 ms
3  69.36.237.29 (69.36.237.29)  5.388 ms  4.296 ms  3.797 ms
4  g2-1.core3.eqx.layer42.net (69.36.239.82)  3.374 ms  18.542 ms
    2.904 ms
5  sjo-ix.he.net (206.223.116.37)  3.292 ms  3.008 ms  3.069 ms
6  pos2-2.gsr12416.pao.he.net (216.218.224.105)  4.157 ms  4.652
    ms  3.929 ms
7  paix-px1--hurricane-ge.cenic.net (198.32.251.69)  42.104 ms
    204.192 ms  214.253 ms
8  dc-oak-dc1--svl-dc1-10ge.cenic.net (137.164.22.31)  43.757 ms
    14.290 ms  17.195 ms
9  dc-csac-dc1--oak-dc1-ge.cenic.net (137.164.22.111)  14.411
    ms  14.102 ms  14.043 ms
10  ucdmc-ge--sac-dc1.cenic.net (137.164.23.74)  42.767 ms
    14.252 ms  15.646 ms
11  unexgal9.ucdmc.ucdavis.edu (152.79.198.9)  14.770 ms
    42.390 ms  17.086 ms
12  unexgal9.ucdmc.ucdavis.edu (152.79.198.9)  46.669 ms
    17.865 ms  15.950 ms
13  unexgal9.ucdmc.ucdavis.edu (152.79.198.9)  45.646 ms
    23.779 ms  19.571 ms
14  * * *

Notice that unexgal9.ucdmc.ucdavis.edu (which is 152.79.198.9)
apparently doesn't realize that 152.79.198.9 is its own IP address, and
keeps trying to forward it on...?

-- 
Micah J. Cowan
Programmer, musician, typesetting enthusiast, gamer...
http://micah.cowan.name/