Archive for the ‘Linux’ Category
Friday, January 4th, 2008
If you have a dedicated Linux server, this list is for you. Below are a few items you need to do, to ensure your 2008 will be a bit brighter. This list is by no means comprehensive, but hopefully gets you started in the right direction this year.
- Check your backups and perform a full system backup (or setup a backup routine! Now!).
If you have backups configured, validate they are actually being run. Check the last date / time of the backups to ensure they are running as expected. If possible, test the restore process.
Perform a full system backup and copy this backup offsite, to a provider like rsync.net
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Tags: Checklist, Linux
Posted in Linux, Quick Tip | No Comments »
Friday, December 7th, 2007
Here was the scenario I faced. RHEL4 machine will not boot (according to data center), receives various library not found errors on bootup (Later, I found these errors were from an intruder who tried to install a rootkit, and it didn’t go so well. Most of /bin was corrupt).
The data center recommends that the operating system be reloaded onto a separate disk, which will become the primary, and then mount the old disk as a different mount point for reference / restore. The data center reloaded the operating system, and the customer then found our services online and asked for assistance.
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Tags: Backup, Linux, Plesk, Restore
Posted in Linux, MySQL, Security | No Comments »
Wednesday, December 5th, 2007
When running a ‘yum check-update’, I would receive an error. The error continued even after running ‘yum clean all’.
The error is shown below:
# yum check-update
Setting up repositories
core 100% |=========================| 1.1 kB 00:00
updates 100% |=========================| 1.2 kB 00:00
extras 100% |=========================| 1.1 kB 00:00
Reading repository metadata in from local files
primary.xml.gz 100% |=========================| 1.0 MB 00:00
Traceback (most recent call last):
File "/usr/bin/yum", line 29, in ?
yummain.main(sys.argv[1:])
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Tags: error, Linux, yum
Posted in Linux | 1 Comment »
Wednesday, October 17th, 2007
We deal with security related issues nearly every day. Many of these issues could be prevented with a few minor changes to php.ini along with the installation of mod_security. It is simply amazing how many machines are hacked, and then used for the sole purpose of sending spam, denial of service (DoS) attacks or Botnets.
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Tags: Apache, Firewall, PHP, Security
Posted in Apache, Linux, Quick Tip, Security | 1 Comment »
Wednesday, October 17th, 2007
You may find this iptables based method of limiting packets useful. For example, to drop connection from from someone who is trying to brute force your passwords via ssh.
I have a particular case, where a customer wants to be notified if more than X number of SMTP connections are being generated from a particular IP address over a period of time.
Here are the commands..
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Tags: brute force, iptables, ssh
Posted in Linux, Quick Tip | 1 Comment »
Wednesday, October 17th, 2007
I was just asked today to provide a quick overview of the steps necessary to rename a filesystem. And here is what I came up with. Please use this information at your own risk, and always ensure you have a backup just in case something does not go well.
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Tags: filesystem, fstab, rename
Posted in Linux, Quick Tip | No Comments »
Saturday, October 13th, 2007
I have recently been working on virtualizing Windows and Linux machines using Xen. A few things popped up along the way and a bit of research was done to make things work properly, these are some of the notes I took.
Depending on the requirements, LVM may make sense for your implementation. One particular advantage is LVM snapshots for backups.
A setup I am working on now consists of 4 systems with a dedicated LVM device, and an lvm based mount point for file based VMs.
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Tags: Linux, Xen
Posted in Linux, Xen | No Comments »
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