Posted on in System Administration
One of the beauties of using a Linux-based Mail Transport Agent (MTA) like Sendmail is the ability to pipe mail into programs. You can use this in conjunction with a filtering application like procmail, with a custom application that collects data about the email, or anything else you can imagine …
Posted on in System Administration
Why is it always a pain to find this stuff in the documentation?
Username: admin
Password: ironport
Posted on in System Administration
I use snmptrapd to catch SNMP traps and then put them into a MySQL database using a pretty generic trap handler. This gives me the opportunity to generate such useful information as:
> SELECT HOUR(time) AS "hour", COUNT(*) AS "bounces" FROM snmptraps
WHERE hostname = 'XXX' AND time > '2011-07-25'
AND trap_oid …Posted on in System Administration
Historically, the RPMforge repository has aimed to create add-on RPMs for RHEL, CentOS, and Scientific Linux. Although their goal was not to replace base packages, avoiding that has not always been possible. In mid-November 2010, RPMforge created the rpmforge-extras and moved all packages that replaced base packages into the repository …
Posted on in System Administration
Posted on in System Administration
In the past, I've written about the usefulness of
using iptables to limit incoming SSH connections.
Although it isn't a replacement for a good password policy, it at least limits
the ability of outsiders to perform a brute-force password attack on your system.
Now that I've started using Ubuntu more …
Posted on in System Administration
Posted on in System Administration
Behold, the benefits of virtualization!
I spent most of the evening preparing to move a few websites. I decided to do some benchmarking just to see what sort of improvement I was getting from the new server setup. Although the old server didn't feel slow when browsing sites, the results …
Posted on in System Administration
Although this process is well documented on the Ubuntu community site, I decided to take notes of the exact steps that I took so that I wouldn't have to fumble through that long document next time. I'm installing the tools in a clean install of Ubuntu 10.04.2 LTS …
Posted on in System Administration
![Wikibon: How Big is the World of Cloud Computing? [Infographic]](https://lh5.googleusercontent.com/_LF9bAucktRs/Tb9LKNPdQPI/AAAAAAAACY8/u1ILrKs4aFQ/s640/wikibon-graphic-how-big-is-the-world.png)
Via: Wikibon
Posted on in System Administration
I was recently struggling to add a Windows shared printer to my MacBook Pro (running Mac OS X 10.6 (Snow Leopard)) until I ran across this post which gave me two important hints:
Posted on in System Administration
I recently had to add over 100 new devices into Cacti.
Believe it or not, you can do this in bulk using the command-line tools provided
with Cacti. I used to
add_device.php,
add_tree.php, and
add_graphs.php
scripts to get the job done.
First, I created a file (/tmp …
Posted on in System Administration
Clearing the Windows DNS Server cache from the command line is an easy task.
C:\> dnscmd . /clearcache
The . indicates the local DNS server. You can use this command to clear the
cache of remote DNS servers by replacing the . with the hostname or IP address
of the remote server.
Posted on in System Administration
Yesterday, Red Hat announced the release of Red Hat Enterprise Linux (RHEL) 6. For those of us interested in virtualization, RHEL brings along many changes.
RHEL 6 promises enhanced virtualization performance in several ways. First, the operating system is now theoretically able to handle 4,096 CPUs, 16 TB …
Posted on in System Administration
If you're using a non-standard MySQL data directory on your Red Hat Enterprise Linux (RHEL) server, you may have seen an error like /usr/libexec/mysqld: Can't change dir to '/mysql_data/' (Errcode: 13). The key to fixing this problem is to ensure the new MySQL data directory has the proper …
