Nginx close upstream connection after request

Nginx was configured as reverse proxy for an upstream server that servers a website. Upon checking the setup I encountered the 502 Bad gateway error. In Nginx error.log I found the following line:

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Disqus and other comments does not show on WordPress

The sympthoms are that neither default WordPress comment box neither Disqus or other commenting system plugin does not show comments on your WordPress website.

The most often reason is misconfiguration in your WordPress. Check the following:

Turning on Comments for a Single Post or Page

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How to remove mod_pagespeed from access.log

If you have mod_pagespeed installed on your webserver you may notice the following lines in access.log file:

Depending on the size of your website requests from mod_pagespeed can add flood your logfiles and their size will be significantly larger. Here is how you can exclude mod_pagespeed requests from access.log file Continue reading

How not to log certain requests in Apache

Apache HTTP Server

By default Apache logs all requests. Sometimes you need to exclude logging of certain requests from Apache‘s access.log. For example some automated requests coming and flood your log distorting your statistics. This short guide shows how you use Apache’s SetEnvIf directive to prevent Apache from logging such requests.

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What is Tomcat shutdown port

In default Tomcat installation, you will find the following line at the top of Tomcat‘s global server configuration file server.xml :

This configuration allows remote shutdown of Tomcat by sending telnet command to port 8005. Something to note:

1. Port 8005 is on TCP protocol. This is important for firewall configuration
2. Port 8005 must be available for Tomcat to start. Use “netstate -an | grep 8005 | grep LISTEN” to confirm prior of Tomcat startup
3. The shutdown command is configurable, and case sensitive. In this default configuration (as above), it must be uppercase SHUTDOWN. It can be configured to other value if there is a security concern.

4. If port number is -1, then remote shutdown is disabled

Following steps illustrate how to shutdown Tomcat remotely (I will login directly to Tomcat server and shut it down by telnet) Continue reading

A fatal error occured during initialisation. JIRA has been locked

atlassian-logoAt some moment Jira app stopped responding. When I stopped and started it Jira failed to start with:

JIRA Startup Failed You cannot access JIRA at present. Look at the table below to identify the reasons Description Unable to clean the cache directory: /opt/jira/plugins/.osgi-plugins/felix

In catalina.out log there were following lines:


There are two known causes for this issue: Continue reading

ORA-09925: Unable To Create Audit Trail File

Upon trying to start Oracle database service I got the following ORA-09925 error in $DB_HOME/startup.log file

The same ORA-09925 error when I tried to log on to SQL*Plus. Continue reading

Configure IAX clients in Asterisk

Asterisk PBX

This article will cover the process of IAX clients configuration in Asterisk.

There are three authentication methods that are supported: MD5, plaintext and RSA. The least secure is “plaintext”, which sends passwords cleartext across the net. “md5” uses a challenge/response md5 sum arrangement, but still requires both ends have plain text access to the secret. “rsa” allows unidirectional secret knowledge through public/private keys. If “rsa” authentication is used, “inkeys” is a list of acceptable public keys on the local system that can be used to authenticate the remote peer, separated by the “:” character. “outkey” is a single, private key to use to authenticate to the other side.

Public keys are named /var/lib/asterisk/keys/<name>.pub while private keys are named /var/lib/asterisk/keys/<name>.key. Private keys should always be 3DES encrypted. Continue reading

Asterisk IAX error No Authority Found

Asterisk PBXThis error is usually caused by a username/secret/type mismatch.

This error also occurs when the context requested in the incoming call is different from one in the section of incoming peer. Multiple contexts in the peer section can be defined. Continue reading

Understanding Asterisk IAX authentication

Asterisk PBX

This article explains the process that Asterisk uses to authenticate incoming and outgoing IAX2 connections. Reference to “type=user” in the text below should be assumed to include “type=friend” as well, since a friend can act as a user. The same assumption holds for “type=peer” references below. Continue reading

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