Posts Categorized: Uncategorized

Test SMTP with Telnet

Useful for finding problems with new installations. telnet 25. Key in “EHLO” and press enter. Key in “MAIL FROM:” and press enter. Key in “RCPT TO:” and press enter. Key in “DATA” and press enter. Optionally add envelope headers (and leave a blank line between these header values and the message… Read more »

Slow SSH Logins

On a new CentOS 5.1 install there was a dleay while logging in via SSH. Using the -v option i.e. # ssh -v jonny@servername gave more verbose output with the following messages: debug1: Authentications that can continue: publickey,gssapi-with-mic,passworddebug1: Next authentication method: gssapi-with-micdebug1: Unspecified GSS failure.  Minor code may provide more informationNo credentials cache founddebug1: Unspecified… Read more »

MySQL Logging Notes

Enabling some extra logging options on MySQL is useful for temporary close analysis of what is actually going on with your server and applications. Logging Slow Queries To switch on the logging of queries which take a long time (default 10 seconds) enter the following line into my.cnf: [mysqld] log-slow-queries This will give details on… Read more »

SSH Tunneling with a MySQL Example

SSH tunnelling can be used to secure communications of non-secure protocols between two computers. For the purposes of this example I have a server running MySQL which I will call . The default port for MySQL is 3306 but by default it does not listen to external requests, only to localhost requests. This is… Read more »

Apache Proxy Pass on Ubuntu

The Apache module mod_proxy can be used to 'reverse proxy' requests through an Apache server to another server. This is most useful when proxying requests to a server behind a firewall which is not directly accessible from the internet. In this example there are 2 servers and There is an application running at… Read more »

MySQL Collation and Character Set

Importing databases from MySQL 3.2 to MySQL 5 – When I create a database using Plesk it creates it as utf8 (Character Set) and utf8_general_ci(Collation) but when I create a database using PhpMyAdmin the database is created as latin1 (Character Set) and latin1_swedish_ci(Collation). The trouble comes when I import sql files into the utf8 database…. Read more »

Apache MaxRequestsPerChild 10000

We found that Apache 1.3 was periodically using up all the memory and swap space on a machine and stumbling on the post below we decided to reduce MaxRequestsPerChild from the apache conf advised value of 10000 for Solaris down to 100 or 500. Hopefully this will reduce susceptibility to memory leaks. —- ORIGINAL MESSAGE… Read more »

Plesk Horde Issues with Sending Mail

For future reference …Had a few issues related to Horde sending mail. Although it appeared as though the mails were sent there was an issue with Horde using Sendmail.One proposed solution was to edit php.ini and amend the disable_functions line in /etc/php.ini and remove the popen and escapeshellcmd functions so that PHP/Horde can use these… Read more »

PHP LDAP Search Root of Active Directory

Using PHP to query Active Directory resulted in a few problems e.g. Warning: ldap_search() [function.ldap-search]: Search: Can’t contact LDAP server in … ldap_search(): Search: Operations errorWarning: ldap_search() [function.ldap-search]: Search: Partial results and referral received The errors only appeared when trying a search from the AD root, the errors disappeared when the search was carried out… Read more »

Prettifying Nagios

The default installation of Nagios is pretty ugly but can be tarted up with the Nuvola icons and some stylesheets from the following page:;d=1 Scroll down the page to the files section and download the Nuvola file. Extract it and copy the contents of the ./html directory into the nagios web directory (/usr/local/nagios/share/html on debian)…. Read more »