Disable HTTP Compression in Apache | I’ll show you a quick way to actively check a server for compression as well as how to disable compression in Apache. Note: This has _no_ effect on the CRIME TLS vulnerability but does mitigate BREACH. | Test for Compression A simple test page to test for HTTP compression is here: http://www.gidnetwork.com/tools/gzip-test.php Or alternatively, below is a manual test for
iostat and vmstat – Awesome System Statistics for Linux | Two excellent Linux apps are iostat and vmstat. These provide realtime statistics of system IO and memory usage. Here’s how it works! iostat iostat is useful to view realtime stats of disk IO. I suggest running ‘iostat 1′ to have the command refresh each second. $ iostat 1 Linux 3.2.0-2-amd64 (brahms) 09/12/2012 _x86_64_ (4 CPU)
clamav Signatures not Updating Ubuntu Linux | Clamav will sometimes have trouble downloading updates for some reason or another. I’ll show you how to fix this in Ubuntu Linux! First, stop clamav: $ sudo /etc/init.d/clamav-daemon stop $ sudo /etc/init.d/clamav-freshclam stop Next we are going to manually download the latest signatures from clamav’s website and place them into the proper location in Ubuntu.
Fast Host Discovery with nmap | The easiest way to do host discovery is with nmap. nmap of course offers a variety of ways to probe and map out detected hosts and poke at any open ports or services. But as for a quick discovery, ICMP is ideal to just get a quick assessment of online hosts. I’ll show you how!
Encode or Decode base64 from the Command Line | If you have ever needed to quickly decode or encode base64, Linux has a command line utility called base64 that works great. I’ll show you how it works! To encode text to base64, use the following syntax: $ echo ‘scottlinux.com rocks’ | base64 c2NvdHRsaW51eC5jb20gcm9ja3MK To decode, use base64 -d. To decode base64, use a syntax
Example Interview Questions for Networking or Linux Jobs | Below are a few good interview questions for networking or Linux related jobs. These will give a relatively good assessment if the candidate has good knowledge of some fundamentals. Alternatively, this makes a great study guide if you are applying for any networking or Linux related jobs. Wikipedia is the best guide and much better
How to Manually Edit ufw Rules on Ubuntu Linux | ufw is the great command line app for managing iptables in Ubuntu. While any changes should use the ufw command, it is possible to rather manually edit user created ufw rules in cases where that might be desirable. The file location is: /lib/ufw/user.rules For ipv6 rules, the file is: /lib/ufw/user6.rules As with iptables, rules are
bing – Measure Bandwidth from Command Line | The command line program bing measures bandwidth between two point to point locations. This is an excellent tool for testing throughput or interfaces. Here is how it works! Install bing: $ sudo apt-get install bing The syntax is: $ sudo bing [host1] [host2] bing works by sending an ICMP echo request and measuring the delay
ss – the alternative to netstat | An alternative to netstat is the utility ss. ss dumps socket statistics in a clear and more simple view as compared to netstat. Let’s check it out! With no options specified, ss displays a list of TCP sockets with established connections. This is useful on a server to see what clients are connected. The option
How to login via SSH to Amazon EC2 instance | After launching a Linux Amazon EC2 instance, you can ssh in by using the private key (key pair download) provided in the AWS console. I’ll show you how! 1. In the AWS console, a key pair can be generated. Download the key pair (private key, .pem file) from the console. 2. Next, move this .pem