Technology Insights

Clear Out Postfix Queue, Analyze Postfix Email Queue

Earlier today we had a minor issue on a development server that generated around 175,000 emails dumped into a Postfix queue in a short amount of time. I needed to first analyze the emails and second clear the Postfix queue. Below is information on how to learn more about the emails in the Postfix queue, what domain they are being sent to, and last but not least delete those emails from the queue if they are not needed.

Information Security

Backtrack 4: Information Gathering: Search Engine: Goorecon – Find emails and subdomains using Google

During the Information Gathering section of a pentest, we are interested in finding out the various sub-domains of our target domain. In the past few tutorials we queried DNS servers using zone transfer requests or trying to retrieve entries using a dictionary & brute-forcing attacks. Another technique to figure out sub-domains is to query google and check if it has found any sub-domains during it’s web mining exercise on the target. Goorecon can do this. Goorecon was written by Carlos (Darkoperator) Perez.

Technology Insights

How To Insert An Accented E or é In An Email Message Composed With Outlook

Recently I have been sending a lot of emails to a colleague in Portugal whose name ends é. While I was told it is not so rude to simply not include the accent above the E I actually prefer to include the accent to display respect since he actually includes the accent over the E in his signature. Since I am using Outlook 2007 the below Outlook keyboard shortcut will provide the easiest method for you to insert an E with an accent over the top in emails that you compose. After information related specifically to the accent over the E I also discuss inserting other non English symbols into email messages composed with Outlook.

Technology Insights

Delete Gmail Messages, Delete All Messages That Match A Specific Search In Gmail

A company I work with uses Gmail to log exception emails from our Ruby on Rails application. This allows us to always capture issues with the application and keep a lengthy history of all the issues without using up disk space on the server itself. Sometimes if there is an issues on a development server that is not fixed right away we may get thousands of emails into the Gmail account that are all the same and it benefits us to clear these out from time to time since they can number over 50,000 at times. The example image below shows our Ruby on Rails application exception inbox from Gmail.

Technology Insights

Remove Amavis Content Filter From Postfix Configuration, Requeue All Postfix Email Messages

I installed ISPConfig awhile back on a web hosting server that at one point also hosted email accounts. I recently moved all of the email to a different server and wanted to cut down on CPU and memory usage so I needed to disable amavisd, clamd, courier-imap, and courier-authlib. These services provided a way to receive email via POP3 and IMAP as well as content filtering and virus scanning for all of that email. So after shutting all of the services down I needed to remove the reference to the local content filter from Postfix because if amavis is shut down and mail is sent from a web application to the localhost then the connection will be refused and Postfix will not send the email. Below I describe the Postfix configuration lines to comment out as well as a way to reload all of the queued email into the Postfix queue so it could be sent again.