31 Mar 2018

SPAM. Does anybody really like it?

Let’s face it, nobody likes receiving spam in their email.

The Green-Light email hosting system has spam filters built in which work pretty well and have been adequate for the last number of years. However, in recent times we’ve been finding our servers being blocked by companies like Microsoft because we’re sending spam.

Usually, when our systems are sending spam it means a users email or website has been compromised in some way which has allowed a spammer to send thousands of unsolicited messages. We’ve made changes over the last year to tighten these holes and set up alarm bells to alert us when these things happen. But still, we’re being blocked on occasion. There has to be something that we’re missing.

Enter the addition of outbound email filtering. Most spam filter systems only filter incoming messages. This is a good way to keep your inbox clean but doesn’t do anything about sending messages which directly affects our reputation and in turn blocks us.

We’ve added two email gateway servers and set up our cPanel servers to send ALL email through them. The first day this was running we successfully stopped over 500 outgoing spam messages we didn’t know were being sent. It turns out the way some users have configured their email (using forwarders) still allows spam through the cPanel filters and appears to be originating from our servers. Not very good. But that has now been stopped.

An added bonus to these mail gateways is the ability to have redundant incoming and outgoing servers. We can take one of them offline to do maintenance or upgrades and the system will stay up and running. With some minor tweaking on your DNS and setup on the gateways, we can also filter all incoming messages for your entire domain.

We’ve been testing the incoming filtering on our own email and so far the results are looking very positive. In time, we’ll start offering the incoming filtering for all of our clients for a nominal fee which is yet to be determined.

Feel free to contact us at help@green-light.ca if you have any questions.

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13 Apr 2017
02 Apr 2017
10 Mar 2017
30 Jan 2017

HyperLoop Pod Competition Held at SpaceX This Weekend

University teams around the world met to test out their designs at the first of two Hyperloop Pod Competitions. SpaceX has spent the last 6 months constructing the world’s second largest low-pressure environment in the form of a one mile test track, second only the famous LHC. 

The Hyperloop track built near SpaceX’s headquarters in Hawthorne, California, since early September allows teams to test vehicles of three main types:  Wheel, Air Bearings and Magnetic levitation. 

Hyperloop Track Spec

SpaceX also constructed a vehicle it calls the Pusher to get pods up to operational speed and outlined basic specifications of a track for students to design their pods around. 

Initial interest in the competition was in the thousands, but by the time of competition only 27  teams actually made it through the rigours of the process. Of those 27 teams only 3 won the right to run their pod in the test track. 

Delft, MIT, and WARR

The competition was one of truly global participation but after a battery of safety and engineering tests conducted Saturday on the 27 pods brought to California only MIT here in America,  WARR of Germany, and DELFT of the Netherlands earned the right to run the track. 

MIT won the award for safety and reliability, while WARR won for fastest pod. DELFT walked away with the best overall score in all categories. 

Eyes to the Future

While it was an exciting weekend for many geeks worldwide, we are already looking forward to this summer when the second competition will take place. Teams will return home with the lessons learned, contacts made and a drive to see how they can improve their PODs for the second competition on a yet to be announced date this summer.

We wish them luck and look forward to further innovation in this exciting transport system. 


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17 Dec 2012
30 Jun 2012
26 Jun 2012
19 Feb 2012

Default wpad.dat on apache

In an effort to run a tighter hosting environment we’ve been centralizing our logs and resolving the most numerous errors generated by the system. One common error on all the servers is clients searching for auto proxy configurations.

File does not exist: /home/user/public_html/wpad.dat
File does not exist: /usr/local/apache/htdocs/wpad.dat

Simple Wpad.dat
In our situation we really just want to remove the error log entry, we want to deliver the simplest version of this file we can. So we don’t get anymore File does not exist errors. The simplest thing to do is to tell the client to simply connect direct. Which is what they are going to do anyway when the file is missing.

function FindProxyForURL(url, host)
return “DIRECT”;

Default include for /usr/local/apache/conf/userdat/missing-wpad.conf
Next we add an include file for our apache installation so any request on any site on our server for this file is redirect to our default file. But only if the client hasn’t uploaded their own version of the file. ( !-f )

RewriteEngine On
RewriteRule  .*wpad.dat$         /usr/local/apache/htdocs/wpad.dat [L]

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18 Dec 2009

Configure Postfix with Relay host and SMTP Authentication

So you want to do something simple like monitor your hard drives S.M.A.R.T status. You go to install the smartmontools package on Ubuntu and your prompted to install Postfix, and your faced with having to setup a mail relay, what a drag.

This is a simple walkthrough on the changes you need to make after Postfix is installed relay all mail generated on your system to an external mail server that requires SMTP Authentication.

When your prompted by the postfix package configuration choose Local Only, the wizard won’t let you setup authentication so we’re going to add the rest manually. Choosing Local Only will only create a basic main.cf for you. Once the install is complete do the following.

Assume Ubuntu 9.04

Add the following lines to /etc/postfix/main.cf

relayhost = [host3.green-light.ca]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options =

Create a new file called /etc/postfix/sasl_passwd

[host3.green-light.ca]:587  user:password

Give that file proper permissions

sudo chown root:root /etc/postfix/sasl_passwd; sudo chmod 0600 /etc/postfix/sasl_passwd

Create the hash database from your sasl_passwd file.

sudo postmap hash:/etc/postfix/sasl_passwd

Reload postfix with your new settings

sudo postfix reload

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