[PLUG] Identifying Why One Web Site Will Not Load [RESOLVED]

[Jim Garrison]

On 9/17/2014 5:28 PM, Rich Shepard wrote:
> Sigh.
> 
>    While agreeing with Michael that it's a problem that should be resolved,
> the best minds here in the linux universe are equally stumped.

One possibility is that the *remote* web server has reverse
DNS validation turned on, and your external IP, for some reason,
does not have a PTR record.  Can you send me (in a private
email) your external IP address?  You can easily determine this
by going to http://whatismyip.com.

Almost all ISPs provide PTR records for their dynamically
assigned pool addresses. For example, my (obfuscated) IP is
 aa.bb.cc.dd and if I do a "dig -x" on it I get:

...
;; ANSWER SECTION:
dd.cc.bb.aa.in-addr.arpa. 5313 IN PTR c-aa-bb-cc-dd.hsd1.or.comcast.net.
...

If your ISP has not provided a PTR record for your address,
then it's the SERVER that could be timing out on DNS resolution
trying to figure out who you are (for blacklisting, for instance).
It's pretty rare nowadays to configure a web server to do PTR
lookup (email servers yes, web servers no) but it would cause
exactly the behavior you are seeing.

-- 
Jim Garrison (jhg at acm.org)
PGP Keys at http://www.jhmg.net RSA 0x04B73B7F DH 0x70738D88