Install New Relic Server Monitor on Ubuntu

I’ve found New Relic to be a great free addition to my suite of tools for server monitoring and alerting as I shifted to a DevOps support environment.

Installation is very fast an simple once you’ve created a free accound. Paid options are available and allow for more features.

You will need to record/save YOUR_LICENSE_KEY from your account for step 5 below.

  1. sudo sh -c 'echo deb newrelic non-free > /etc/apt/sources.list.d/newrelic.list'
  2. wget -O- | sudo apt-key add -
  3. sudo apt-get update
  4. sudo apt-get install newrelic-sysmond
  5. sudo nrsysmond-config --set license_key=YOUR_LICENSE_KEY
  6. sudo /etc/init.d/newrelic-sysmond start

You are done! Within a few minutes you should start seeing data on your consoles at the New Relic website.


Comcast Business Class gateway forwarding port 22 for SSH

For as long as I’ve had Comcast, and other providers for that matter, I’ve been able to configure my internet gateway/router to allow port 22 (SSH) access to an internal machine. It came as a surprise to me earlier this week that I was blocked when I tried to use their web admin console to change the internal forwarding to a newer machine. As usual, Technical Support was less that helpful and said that it was not possible to do so, and never should have been as Comcast uses that port to administer the gateway. To make matters more disturbing, I was told that I could not have similar SSH access to the gateway, and that replacing their hardware, while permitted, would prevent my use of a static IP.

Back to the solution, as I know that I had only setup this forwarding about a year ago, and it was working only minutes before I tried to change it, I knew that the configuration was possible if I could figure out how it was being blocked. The message in the web console was a javascript alert(); and gave me a starting point. I opened up Firefox and used Firebug to look for the message. Here are a few interesting findings from:


var RemoteManagementPortsCgiBase = “8080,8080,1\|8181,8181,1\|2323,2323,1\|22,22,1\|”;

msg += “Public Port Range conflict with Remote Management Ports.\n”;

if (msg.length > 1)
return false;
return true;

If you even a little bit of javascript (or simple computer programming for that matter), the solution is clear…. if the ‘msg’ value is empty you will not see the alert or be prevented from making the change you desire.

Lesson to be learned by the Comcast developers (or most likely = subcontractors), always validate submitted form data in your application code, NEVER rely upon javascript alone to verify user entered data!

I also find it interesting that they are also preventing 8080, 8081 and 2323… perhaps that’s their other back doors in these gateways for their access. The same approach should work for those ports if you need it!

No JavaScript support

There are still a measurable number of internet users that browse without the use of JavaScript, use the NoScript plugin, or have disabled it for security purposes. In those cases, as well as for SEO. It’s often a good idea to manipulate the display to better accomodate these users. One of the most common methods is shown below, as we can toggle a CSS class on the HTML tag easily and use CSS “cascade” to hide or show alternate content.

NOTE: this example currently requires PrototypeJS, but can easily be changed to not do so.

<!DOCTYPE html>
<html class="no-js">
<script type="text/javascript">
var ar = document.getElementsByTagName('html');
var i = ar.length;// should only be one!
<style type="text/css>
html .no-js-show { display:none; } .no-js-show { display:block; } .no-js-hide { display:none; }
JavaScript is:
<p class="no-js-hide">enabled</p>
<p class="no-js-show">JavaScript is disabled</p>