Key Based Authentication in SSH

March 5, 2010 Posted in Security

I just changed my SSH authentication from password to key-based. If you are using password authentication, I strongly suggest you change it, it’s a must, the setup is also very easy, there is no any reasons you don’t do this. With all kinds of buggy programs and scripts, our servers are much much weaker than we thought.

Edit: Wrote a step by step guide for easy reference.

Tar: extract one or more files from an archive

February 22, 2010 Posted in Command & Utility

To extract a single file from an archive:
# tar zxvf tarfile.tgz –include=”desiredfile”

Use patterns:
# tar zxvf tarfile.tgz –include=”desiredfile*”

‘desiredfile’ must use full path. To check file’s fullpath:

# tar tf tarfile.tgz

Note: It’s double ‘-’ before include.

vBulletin Forum Hack

December 27, 2009 Posted in FreeBSD General

My vBulletin forum was hacked, the gate was vBseo according to this thread,

I always upgrade as soon as I receive their update email, later I realized vBSEO has two different versions for version 3.2.2?! Have you ever seen anything like this:

vBSEO 3.3.2
Release date: October 27, 2009
Last Updated: November 17, 2009

I upgraded to the first 3.3.2 but missed the second.
Read More

Urgent Security Warning for WordPress

September 5, 2009 Posted in Security

I just found that my two wordpress blogs were hacked, the permanent link structure was changed to:


This caused the individual posts couldn’t be accessed.

I don’t know how this was hacked, and what other damages were caused. For now, a urgent solution would be protecting wp-admin directory.

I have seen some other hacked blogs, I strongly suggest you take actions immediately. The above might not be a good solution, but should be helpful.

Stop the Most Annoying Spammers

August 3, 2009 Posted in Apache, MySQL

Some spammers are very stupid and persistent,  they don’t care about the results, and keep spamming for months and even years. They combine manual and automate ways to post spams, the only way to stop them is blocking their IPs.

Read More

.htaccess error

July 19, 2009 Posted in Apache

My site got ‘internal server configuration’ errors, the Apache error log file for this domain has the following error message:

.htaccess: order takes one argument, ‘allow,deny’, ‘deny,allow’, or ‘mutual-failure’

Read More

How to Stop a Cron Job or Email Notification

March 30, 2009 Posted in FreeBSD General

From the log stats, I found many people were wondering how to stop a cron job or its email notification. To stop a cron job, just remove the command by editing the cron job: Read More

Scary Moment

March 30, 2009 Posted in Security

When I was restarting Apache after installed a new PHP module, I found that httpd.conf was missing, that was scary! I have absolutely no idea how this happened, the only possible reason is that I deleted it by accident. Read More

Converted to WordPress

March 18, 2009 Posted in Misc

MovableType suddenly stopped working, I couldn’t publish new posts any more. So I took the chance to convert it to WordPress.

Another FreeBSD Blog

March 13, 2009 Posted in FreeBSD General

Here is another FreeBSD blog: Real FreeBSD Tips, it looks quite professional. Still too few FreeBSd blogs out there, FreeBSD deserves much more attention. I have no idea how many servers are running FreeBSD, but it should be a very small number compared to Linux.

Email ISP

March 12, 2009 Posted in Email

Finally, AOL unblocked my new IP, their Feedback Loop Request Form doesn’t seem to work, I joined two times and was approved too, but nothing happened. The unblock was done after I got a personal reply to my direct email request.

Here are some other email ISPs I have dealt with: Read More

Official FreeBSD Forum

March 9, 2009 Posted in FreeBSD General

I just found the official FreeBSD forums, it’s also using my favorite forum software, nice. I prefer web-based forums to milling-lists, newsgroups or IRC rooms, I can never get used to them. Finally, I got a place to hang out.

Move a Server

March 8, 2009 Posted in FreeBSD General

In the last 6 months, I have rebuilt my server four times due to ISP change or hard disk problems. Minimal down time and data consistency are two most factors when move to a new server. Here’s how I usually move a server: Read More

Moved Out

March 4, 2009 Posted in General

The problem, which should never have happened, happened again just two days later, caused another 4 hours down time. must hate me, I can’t understand why they stopped routing my IPs, again!
Read More

Monitor MySQL Log File

March 2, 2009 Posted in MySQL

I rarely check MySQL log file, but recently I got some table corruption errors, and it’s hard to notice these errors, especially when these tables are not critical. I realized that it’s necessary to monitor MySQL log file. According to MySQL manual, before version 5.1.20, it’s not possible to log MySQL errors to syslog. I’m still using 5.0, so I added the following line to cron job of my root account:

30 2 * * * tail -n 50 /var/db/mysql/hostname.err

Now I get notification email daily (no email if it’s empty), not a bad solution.

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