One thing that can be really helpful for Linux administrators is sending mail attachments via the Linux command line. It is fairly widely known that you can inject text files into email by piping the outputs of those files to the mail command however something that is less known is attaching files to an email sent via mail. The information below describes how to send mail from a Linux shell using the mail command.
While working on a project unrelated to Postfix on a CentOS server I noticed an error in the mail logs that indicated an issue with the root users mailbox. I have yet to locate the root cause of the problem however I was able to resolve the problem easily. Below I explain the error in more detail as well as how I was able to resolve the problem with sending email to the root users inbox.
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.
I discovered something really cool tonight to help organize my default Gmail account. You can use an unlimited number of aliases which in return will allow you to easily filter or organize incoming email based on numerous factors. By default Gmail will deliver any mail with your username+anystringhere@gmail.com to your Gmail inbox. This not only works with @gmail.com email addresses but it will also work with any domains you have hosted via Google apps.
A client of mine that still uses Outlook Express called me because they were unable to receive mail on one of their PC’s. After a little troubleshooting I determined that there was nothing wrong with the account itself but it appeared the issue was on the computer. The specific error they were receiving is below.
Error:An unkown error has occurred. Account: ‘mail.example.com’, Server: ‘mail.example’, Protocol: POP3, Port: 110, Secure(SSL): No, Error Number: 0x800C0133