Warning about email attachments
Due to the restrictions of the email provider which my University uses (GMail), several extensions (like .com, .ins,...) are blocked, even if the file is compressed (.zip, .rar, .tar.gz, .7z,...). One of the 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.
I think that other servers, like "@hotmail.com", have something similar. Altought they do not block compressed files yet. At least, "@hotmail.com" with compressed .ins. But, in any case, it is better to ensure...
Take into account that Google rejects all the email 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
If you are in doubt, please do not hesitate to read the official list of blocked extensions and files. Thank you for your understanding. If you feel this is stupid, and would not like to have this restriction in your own email system, please claim Google through their Help Forum or my post in Spanish.