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A communication error occurred: Connection refused

asked 2018-11-12 06:37:15 -0500

michel.settembrino gravatar image

Hi everybody,

I'm new with openstack and I created my first instance some days ago.

I installed a LAMP following this tutorial: (

But when I do a spot check to see the default apache2 page using the public IP (and from another machine) I am getting next error in my browser:

Network Error (tcp_error) 

A communication error occurred: "Connection refused"
The Web Server may be down, too busy, or experiencing other problems preventing it from responding to requests. You may wish to try again at a later time.

For assistance, contact your network support team.

I can reach and login to my instance using SSH and I can ping it and receive a feedback.

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I doubt this has naything to do with OpenStack. Your instance doesn’t block HTTP requests, but there is nothing that accepts them. As root, run ss -ltnp to check if a process listens on ports 80 or 443.

Bernd Bausch gravatar imageBernd Bausch ( 2018-11-12 07:49:09 -0500 )edit

A few things I would do:

  • Double-check if the IP address is really associated with this instance.
  • Instead of a browser, use netcat to access the instance.
  • Instead of Apache, use netcat to play the server role on the instance.
  • Trace packets with tcpdump
Bernd Bausch gravatar imageBernd Bausch ( 2018-11-12 09:07:31 -0500 )edit

Found the solution. Port 80 was not allowed in default Security Group Rules I used. Allowing port 80 solved my issue.

michel.settembrino gravatar imagemichel.settembrino ( 2018-11-12 09:07:35 -0500 )edit

2 answers

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answered 2018-11-14 12:20:46 -0500

reynoni gravatar image

For clarity and future readers, the solution was to allow traffic across port 80 through a security group within openstack which can be done from the GUI or CLI.

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answered 2018-11-12 08:13:46 -0500

michel.settembrino gravatar image

The result of sudo ss -ltnp is:

State     Recv-Q     Send-Q          Local Address:Port         Peer Address:Port
LISTEN    0          65            *        users:(("mysqld",pid=14492,fd=29))
LISTEN    0          128         *        users:(("systemd-resolve",pid=24025,fd=13))
LISTEN    0          128               *        users:(("sshd",pid=3539,fd=3))
LISTEN    0          128                         *:80                      *:*        users:(("apache2",pid=16929,fd=4),("apache2",pid=16928,fd=4),("apache2",pid=16927,fd=4),("apache2",pid=16926,fd=4),("apache2",pid=16925,fd=4),("apache2",pid=16924,fd=4),("apache2",pid=16923,fd=4),("apache2",pid=16922,fd=4),("apache2",pid=16921,fd=4),("apache2",pid=16920,fd=4),("apache2",pid=16919,fd=4),("apache2",pid=16918,fd=4),("apache2",pid=16917,fd=4),("apache2",pid=16916,fd=4),("apache2",pid=16915,fd=4),("apache2",pid=16914,fd=4),("apache2",pid=16913,fd=4),("apache2",pid=16912,fd=4),("apache2",pid=16911,fd=4),("apache2",pid=16910,fd=4),("apache2",pid=16909,fd=4),("apache2",pid=16908,fd=4),("apache2",pid=16907,fd=4),("apache2",pid=16906,fd=4),("apache2",pid=16905,fd=4),("apache2",pid=16904,fd=4),("apache2",pid=16903,fd=4),("apache2",pid=16902,fd=4),("apache2",pid=16901,fd=4),("apache2",pid=16900,fd=4),("apache2",pid=16899,fd=4),("apache2",pid=16895,fd=4),("apache2",pid=16894,fd=4),("apache2",pid=16893,fd=4),("apache2",pid=16892,fd=4),("apache2",pid=16887,fd=4))
LISTEN    0          128                      [::]:22                   [::]:*        users:(("sshd",pid=3539,fd=4))

Can you please suggest?

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Asked: 2018-11-12 06:37:15 -0500

Seen: 504 times

Last updated: Nov 14 '18