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Re: Connection refused - subdomain problem suspected

From: Richard Elen via curl-library <curl-library_at_cool.haxx.se>
Date: Thu, 5 Sep 2019 20:28:03 +0100

Hi Christopher and thanks for the comments from you and other respondents.

To answer your question:

  * A PHP script on the "admin" server can successfully make a Curl
    connection to all other hosts we've tried.
  * In addition, a PHP script on ANY OTHER machine we've tried can
    successfully make a Curl connection with the "streams" host.

It's solely that we can't get a script on "admin" to make a successful
Curl connection with "streams".

My suspicion at this point is that we have a DNS issue, though I don't
know what it might be. The domain is hosted by a third party and on
their system we have A records for both "streams" and "admin" - but
that's all. "streams" has been running successfully for two years
without any evident DNS issues.

The "admin" host is a cPanel system from our hosting provider - with the
limitations on access that implies. The "streams" host is a dedicated
Linux server.

I am wondering what would happen if I deleted the A record for the
"admin" machine and simply used its default hostname as given by our
service provider. It's not going to be a publicly-accessed machine anyway.

Doing a few searches I see that it is apparently not unknown to get curl
connection failures on two hosts within the same domain, but there
doesn't seem to be a consistent cause. Can anyone shed any light on this?

Thanks!

--Richard E

On 05-Sep-19 18:18, Christopher Head wrote:
> A quick idea for debugging: can a PHP script on the same server make a Curl connection to some other target? If yes, suspect firewall or DNS issues. If no, but a command line curl invocation works, then I would suspect a PHP issue on that particular install. Not sure if safe mode or something similar still exists in PHP; if so, perhaps that is denying outbound connections?

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Received on 2019-09-05