E-mail

Intro

You use email directly using a webmail client : http://squirrel.science.ru.nl.

An email client works with two servers :

• a receiving server which you can access using the IMAP protocol.
• a sending server which you can access using the SMTP protocol.

Note: all email will be stored on the receiving (IMAP) server and not on your home directory.

Cncz has a page about configuring email at : http://wiki.science.ru.nl/cncz/Categorie:Email?setlang=en.

Configuring Email client

1. make in your email program a new account with the following settings
   
   • IMAP protocol
     
   • mailserver: post.science.ru.nl
   • turn on TSL or SSL security (IMAP than uses port 993 )
2. add in your email program a new sending (SMTP) server :
   • SMTP-server : smtp.science.ru.nl
   • Turn TLS on! Authentication is only allowed if TLS is used. Sometimes this is called STARTTLS (Eudora) or SSL (Outlook, Pine).
   • port : 25
     
3. In your email client you can now make new folders under your Inbox folder. These new folders can be used to store mails from your Inbox folder by using drag and drop.

Remarks

• IMAP uses TSL/SSL, but SMTP uses TSL!
  
• With IMAP you cannot turn SSL off!
  
• With SMTP you can turn TLS off  and it then still works on port 25. However when TLS is turned of authentication is disabled and you will be disallowed to connect to the SMTP server when you are outside the university network. SMTP can use TLS or not!
• For SMTP I advice to always keep TSL turned on.
  

More information

• http://wiki.science.ru.nl/cncz/Categorie:Email?setlang=en
• thunderbird users : (dutch only) http://wiki.science.ru.nl/cncz/Thunderbird
• Authenticated SMTP

Addressbook

An address book for the FNWI is available : http://wiki.science.ru.nl/cncz/Ldap_adresboek

Mailing lists

There are simple lists of mail addresses possible, which can be requested through Postmaster and after that maintained by the owners themselves, see : http://wiki.science.ru.nl/cncz/Categorie:Email#.5Bnl.5DMailing_lijsten.5B.2Fnl.5D.5Ben.5DMailing_lists.5B.2Fen.5D

Spam filter

By default a spam filter is applied on your incoming,forwarded and outgoing email. Mail which is marked as spam is automatically moved to the Spam imap folder. Note: if your email client doesn't show the Spam imap folder then you still must subscribe the email program to show this folder.

You can configure the level of filtering in the "doe het zelf" (do it yourself)  website by choosing from 4 levels :

• none: no blocking takes place.
• light: blocking by using the C&CZ's own white- and blacklists  : whitelist.sci.kun.nl, blacklist.sci.kun.nl
• medium: also use lists from : bl.spamcop.net and sbl.spamhaus.org
• heavy: On top of the 'medium' lists also use lists from : dnsbl.sorbs.net and xbl.spamhaus.org

New logins automatically get the 'medium' blocklevel. This has a small risk that wanted mail will be blocked, but it clearly blocks more spam for most users than the 'light' blocklevel. Mail that would be blocked by a heavier blocklevel, is let through, but with a warning sign (X-Would-Be-Blocked-By:).

For more details look at the C&CZ website about spam.

Virus filter

By default a virus filter is applied on your incoming,forwarded and outgoing email.

If a mail contains an attachment with dangerous content, this mail is put into quarantine. The mail without the dangerous attachment, but with an attachment that explains what has happened, is marked as virus and is automatically moved to the Virus imap folder. Note: if your email client doesn't show the Virus imap folder then you still must subscribe the email program to show this folder.

An attachment is considered dangerous if it is an executable program, e.g. .exe, .bat, .dll. Since MS-Windows considers zip-files to be directories, and therefore viruses in zip-files appeared, we also consider an executable in a zip-file to be dangerous. In order not to make the list too long (a zip-file in a zip-file in ..., the Dutch chocolate Droste-effect), we also consider a zip-file in a zip-file to be dangerous.

For more details look at the C&CZ website about virus filtering.

Custom Server Filtering with Sieve

http://sieve.mozdev.org

Sieve is a powerful script language for server-side mail filtering. It is intended to be used with IMAP and thus it is widely spread. Many IMAP Server are already sieved, this means capable of running sieve filters. Sieve stores and runs all script on the server-side.

Sieve scripts filter incoming email, and Sieve Scripts are run on the server side therefore you need an IMAP Account, which supports Sieve!

Message stores are commonly sealed servers so you cannot log into them, yet users must be able to update their scripts on them. The Thunderbird Sieve Extension implements the Manage Sieve protocol for securely managing Sieve scripts on a remote server.

For configuring Sieve see: http://wiki.science.ru.nl/cncz/Email_sieve