Warning about email attachments

Due to the restrictions some email providers set, several extensions (like .com, .ins,...) are blocked, even if the file is compressed (.zip, .rar, .tar.gz, .7z,...). One of the commonly blocked extensions (.ins) is, furthermore, used by LaTeX packages and templates. Google even threats to block any file which "seems invalid". And compressed files inside another compresed file. Some of the provides, like GMail, rejects all the emails without notifying me at all!!

So, if you want to send me any file with "uncommon extensions" (not just the usual .pdf, .doc,...), or an "non-standard pdf, doc, odt...", please send me it within a compressed package and protect it by password. Of course, do not forget to tell me which password you have used. And ensure the file list is encrypted. This is not the default option, and Google rejects even encrypted files if it can read the extensions inside. For example, in Linux you can use 7-zip as

> 7z a -mhe=on -p archive.7z a_directory

Many thanks you for your understanding.