Cleaning Up Memory Usage
- May
- 06
I noticed my Ubuntu desktop was using a rather large portion of available memory. I usually have a lot running on my system, multiple terminals, background jobs, etc so this is nothing unusual. Today however I noticed my system was sluggish so I started digging. Memory use was near 100%. I closed all of my […]
read morevi & vim aids
- Apr
- 10
For my quick reference. To open two files in vi/vim and edit side by side (use CTRL-W + w to switch between the files): # vim -O foo.txt bar.txt To open a file and automatically move the cursor to a particular line number (for example line 80) # vi +80 ~/.ssh/known_hosts To display line numbers along the […]
read moreDenyhosts Assists
- Apr
- 10
Every so often a legitimate user will get blocked by deny hosts. When this happens you can re-enable their access with these 8 simple steps (UPDATE: or use the faster version, see below): Stop DenyHosts # service denyhosts stop Remove the IP address from /etc/hosts.deny Edit /var/lib/denyhosts/hosts and remove the lines containing the IP address. […]
read moreTesting Database Connectivity
- Mar
- 31
Working with databases and new application installations can be really fun. Problem is, when there is a problem, everyone starts the blame game. Nothing unusual about that, part of an administrators job is to troubleshoot and prove where the problem starts. When dealing with external databases, there can be numerous problem, the firewall could be […]
read morePain often equals Progress
- Nov
- 07
It has been one of those weeks. Not fun, to many hours worked, personal events missed, you know the kind of week I am talking about. If not…what do you do for a living?! Despite all the pain and stress this week has resulted in Progress, an increased understanding of certain products and new ways […]
read moreSSH – weak ciphers and mac algorithms
- Jun
- 25
A security scan turned up two SSH vulnerabilities: SSH Server CBC Mode Ciphers Enabled SSH Weak MAC Algorithms Enabled To correct this problem I changed the /etc/sshd_config file to: # default is aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128, # aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc, # aes256-cbc,arcfour # you can removed the cbc ciphers by adding the line Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,arcfour # default is hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 # […]
read moreThe Root of Missing Mail
- Apr
- 30
Like all conscientious system administrator I like to keep tabs on my servers. One way of doing this is checking root’s email daily. This is a great idea if you have a few servers and never take vacation! I manage close to 100 servers, so I need a more efficient way of “hearing” my servers […]
read moreRemember when you issued that command…?
- Jan
- 06
Bash History: Display Date And Time For Each Command When working in a clustered environment where sometimes documentation gets written past, it is often helpful to know when you issued certain commands. The bash history is great except it doesn’t include a date/time stamp by default. Here is how to add one: To display the […]
read moreRunning the Citrix Reciever on Linux
- Nov
- 22
Setting up a new linux workstation and after installing the Citrix Receiver and attempting to start a module (Outlook) I got the dread SSL error: Having run into this every 6 months or so I decided it was time to … Continue reading →
read moreFlush This!
- Aug
- 06
I came across this today and learned something new so thought I would share it here. After killing 2 processes that had hung I noticed the following in the ps output: root 373 2 0 Jun11 ? 00:00:00 [kdmflush] root 375 2 0 Jun11 ? 00:00:00 [kdmflush] root 863 2 0 Jun11 ? 00:00:00 [kdmflush] […]
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