Linux System Admins Blog

APC (Alternative PHP Cache) is a free, open, and robust framework for caching and optimizing PHP intermediate code. APC is a great tool to speed up a php driven site and I can’t even think of a big site running on a php framework without an opcode cache (other good choices are eaccelerator or xcache). [...]

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I noticed lots of email being relayed on one of our shared hosting server, CentOS5 with Cpanel and running Exim, and the strange thing is that the email server (MX) for these accounts are pointing to Google (GoogleApps), and we have correct entries for localdomains and remotedomains for these account. The relayers (‘From’ server/address) [...]

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Typically Squid caching proxy server listen and outgoing IP address are the same. Sometimes, for various reasons we want to alter the outgoing IP address. The new address must first be brought up as an interface on the squid server. In squid.conf look for tcp_outgoing_address line, uncomment it and replace the default IP value with [...]

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If you are using a shared server, or just have a limited account on your company servers, you might not have access to your php configuration file php.ini (this is usually found under /etc/php.ini in rhel/centos and /etc/php5/apache2/php.ini in debian/ubuntu). Still, in many situations it might be needed to enable php errors in the browser [...]

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After a long development time, Centos 4.8 was finally released on the 21st August. This is a good thing that after the latest problems between the centos developers, they were able to pull this out finally and now be able to focus on the upcoming 5.4 release.
There are no major changes in this update, mostly [...]

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This quick post will show how we can easily allow only certain http referrers see some location using nginx. This might be useful for example if you are using nginx as a static content provider and want to not allow everyone hot-linking your images and only your own sites. Doing something like this in nginx [...]

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Many people use subversion over ssh for a simple and secure way to work on remotely hosted svn repositories. This is normally as simple as running:
svn co svn+ssh://user@server/repo .
If the remote ssh server is not running on the default ssh port (tcp 22) then this needs a little tweaking to get it working. Normally I [...]

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We will celebrate the Linux System Administrator Appriciation day tomorrow. Yes, there is such a thing, if its in wikipedia (wiki system administrator appreciation Day), than it must be true!
See what its all about here:
System Administrator Appreciation Day, also known as Sysadmin Day, SysAdminDay or SAAD, was created by system administrator Ted Kekatos. Kekatos was inspired to create [...]

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When using cPanel the way to enable allow_url_include directive locally (per user) is to create an Virtual Host include:
First create an include file:
/usr/local/apache/conf/userdata/std/2/username/domain.com/custom.conf
Add directive to custom.conf:

php_admin_flag allow_url_include On

Then run to enable include:
/scripts/ensure_vhost_includes –user=username –verbose
Alternatively, enabling allow_url_include globally (server-wide) is done by editing /usr/local/lib/php.ini and adding “allow_url_include = On” directive to the Fopen wrapper section.
;;;;;;;;;;;;;;;;;;
; [...]

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Are you often waiting over 1 minute to get a ssh prompt? This can be caused by several things however more often then not is a missing PTR record for server address and enabled GSSAPIAuthentication in ssh_config. GSSAPIAuthentiction is Kerberos 5 centralized authentication/authorization mechanism that relies on resolving a hostname for proper operation, when it [...]

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