I was messing around the other day with RSA encryption and came across the site http://nmichaels.org/rsa.py. It demonstrates how to use RSA encryption to encrypt/decrypt a text string. I was interested in the key generation for this, this page just has a generate button however, I wanted to understand how I could generate my own Public Modulus, Public Exponent & Private Exponent in the hexdecimal format. Continue reading
This article attempts to document how to configure Dovecot and domain & users’ mailbox quota sizes using information contained within PostfixAdmin and its associated tables.
During PostfixAdmin install time, the database is requested where PostfixAdmin can store additional tables. Selecting the same database as postfix itself neatly installs these additional tables, that can then be used by Dovecot to monitor mailbox quota sizes. Continue reading
This article sets out the steps needed to support multiple domains and their users’ email accounts allowing them to recieve emails via secure IMAP and send emails via a secure SMTP server using their POP3/IMAP credentials. This is particularly useful for mobile users (road warrior) who may not have a consistent ISP provided SMTP server.
- Recieve emails, using IMAPS or POP3S via Dovecot
- Configuring Postfix to receive and send emails for virtual domain, and emails accounts
- Configure SASL to provide a method of authenticating users email users to allow them access to the Postfix SMTP in order to send emails securely.
- Easy delegated management of virtual domain mailboxes using PostfixAdmin
This article has been put together from countless other articles so that it should provide an all inclusive set of instructions.
I have been messing around with backing up a compact flash card and trying to put images onto an sd card for my Raspberry PI and thought I would jot down effective use of the Linux DD utility. The ‘dd’ command is one of the original Unix utilities and should be avaliable in all Linux distros. It can strip headers, extract parts of binary files and write into the middle of floppy disks; it is used by the Linux kernel Makefiles to make boot images. It can be used to copy and convert magnetic tape formats, convert between ASCII and EBCDIC, swap bytes, and force to upper and lowercase. Continue reading
MD5 is a one-way algorithm as defined by the RFC1321 that can be used to verify the integrity of a file or filesystem by providing as 128bit digital signature. This digital signature is like a fingerprint for a file or filesystem and will change dramatically even if a single byte changes.
This means they are excellent in checking the integrity of a file that you have downloaded of a mirror that provides the files equivalent MD5Checksum. Continue reading