Frequently asked questions about IMAP and the answers
Introduction to IMAP
IMAP stands for Internet Messaging Access Protocol. IMAP stores e-mail on the IMAP server (mail.rpi.edu). Stored e-mail can be read, replied to, deleted, moved to folders, and searched on the server using any IMAP-capable e-mail client. IMAP clients include Webmail, Outlook, Eudora (Windows and MacOS), Thunderbird; Pine, Kmail and Evolution on Linux; ChatterEmail, SnapperMail (Enterprise) on PalmOS; MacOS X Mail and Entourage on MacOS, Mulberry(Windows, MacOS and Linux), and many others.
Since e-mail is stored on the server, you are not limited to using only one e-mail client, or even one client at a time. You can, for example, use Webmail from an internet Kiosk, Outlook on your office desktop, and Thunderbird at home. Each client will present the same view of e-mail. Responding to an e-mail at home will, if Thunderbird is configured to do so, put the response in the same Sent folder you will view from Webmail. Messages read from Webmail on the road, will have the read-message flag set when you return to work. E-mail deleted over the weekend while at home, will not reappear on your work machine come Monday.
By contrast, each POP3 client presents its own, personal, view of e-mail. If you delete a message from Eudora, it may still be downloaded by Webmail when you get home, requiring you to delete it again.
In addition, e-mail stored on the IMAP server is available 24/7, and is backed up on a daily basis for disaster recovery. If you are not always "wired," most clients can operate in off-line or "disconnected" mode, downloading new e-mail and uploading new messages when the client reconnects. In this way, IMAP can be used with laptops even when an Internet connection is not available.
Wikipedia has a useful comparison of IMAP and POP3 at http://en.wikipedia.org/wiki/Imap#Advantages_over_POP3.
Why does new email only show up when I use Webmail?
This happens when your email client is configured for IMAP, but the email system still has your account configured as a Legacy POP3 user. Email to Legacy POP3 users (those reading email using POP3, or by Wemail and POP3) is sent to the old POP3 server.
If you are switching to IMAP, read the Migrating to IMAP page noting particularly step 6.
After June 30th POP3 service will be merged with IMAP service and this step will no longer be needed.
Can I archive my email, or must I keep it all on the server?
You can archive email with IMAP just the same as with POP3. Most email clients make a distinction between ``local'' files and ``IMAP'' files. Archiving is just a matter of copying, or moving, files from the IMAP portion to the local portion.
Once files are on in the local folders they are no longer available to other email clients. The usual practice is to identify the archiving client, and use that to keep a copy of all archived email. Ideally this client should be choosen for maximum portability of stored files, and it would be backed up on a regular basis. The IMAP client used for archiving does not need to be the same as the client used for reading email.
Some clients, such as Outlook 2003 and 2007, have an auto-archive facility that can, for example, archive all email older than 60 days to a local pst file. Also available for Windows clients is the free IMAPSize utility, which can archive email to local folders.
Does RPI's IMAP server support server-side (SIEVE) filters?
Yes, but you need to create the filters using a client that includes a SIEVE filter editor. At this time, we know of Mulbery and later versions of Kmail. Mulbery is available in Linux, WIndows and MacOS versions, so there is a SIEVE filter editor available for the three most common platforms.
Note: You do not have to use the same client for reading email as you use for editing SIEVE filters. Once a filter is installed on the server it continues to operate, even when disconnected, regardless of the client used to read IMAP email.
I am deleting messages, but I'm still over quota.
Some email clients (e.g., Outlook) do not remove deleted messags from the IMAP server. Instead the messages are marked to be ``Deleted". They may be displayed greyed out, or with a line through the message entry.
To actually delete the messages, the folder must be "purged" or "expunged" or "compressed." How this is done varies from client to client, so read the documentation. If the client offers an Auto-Purge/Expunge/Compress option, you may want to enable it.
You can also use the windows program IMAPSize which offers an Expunge option, as well as attachment saving/removing, and auto-archive operations.
Webmail offers an auto-purge/expunge option.
I am over quota, what can I do?
Simply put: remove files from the IMAP server.
First, if you are using a "trash" folder, empty it.
Second, delete files you do not need. Don't forget to check for old messages---especially messages with attachments---in the "sent items" folder(s).
Note 1: If the files are large, you might not be able to delete them without first disabling the "trash" folder. This is because IMAP will attempt to copy the message to the "trash" folder first.
Note 2: Some e-mail clients do not removed deleted messages from the IMAP server. Instead the messages are marked "Delete". They may be displayed greyed out, or with a line through the message entry. To actually delete the messages, the folder must be "purged" or "expunged." How this is done varies from client to client, so read the documentation. If the client offers an Auto-Purge option, you may want to enable it. (The windows program IMAPSize offers an Expunge option. Webmail auto-purges/expunges.)
Note, if you use more than one IMAP client to read e-mail, those clients may have created their own "trash" and "sent items" folders. Don't forget to check them for unwanted messages. (See Why do I have more than one trash folder?, and Why do I have more than one "Sent" folder? for more information.)
Finally, you can archive old e-mail on your desktop or laptop computer. Outlook has an Auto-archive feature which will move old e-mail to a PST file. You can also use an IMAP archiving program such as IMAPSize.
Why do I have more than one "Sent'' folder?
E-mail clients create sent items folders on the IMAP server. Sent items folders are used to store copies of e-mail you send to other people.
Alas, e-mail clients do not agree on what to call the Sent items folder. Webmail creates a folder named "Sent". Another client may create a folder called "Sent Items", and another "Sent-Items" and so on. If you are no longer using the other clients, you can delete the unused "sent" folders. If you do use more than one IMAP client, you may be able to configure them all to use a common name for the "Sent" folder.
If you used the old Webmail client (prior to August 2005), you may have several sent folders corresponding to the year and month the e-mail was sent. You can combine these into a single "Sent" folder, or delete them. The new Webmail, by default, creates a single folder called "Sent" for copies of outgoing e-mail messages.
Why do I have more than one "Trash'' folder?
E-mail clients create trash folders on the IMAP server to store recently deleted messages.
Alas, e-mail clients do not agree on what to call the trash folder. Webmail creates a folder named "TRASH". Another client may create a folder called "Trash", another "Garbage", another "Deleted-Items", etc. If you are not using the the other clients, you can delete the unused "trash" folders.
If you do use more than one IMAP client, you may be able to configure them all to use a common name for the "trash" folder.
- Introduction to IMAP
- Why does new email only show up when I use Webmail?
- Can I archive my email, or must I keep it all on the server?
- Does RPI's IMAP server support server-side (SIEVE) filters?
- I am deleting messages, but I'm still over quota.
- I am over quota, what can I do?
- Why do I have more than one "Sent" folder?
- Why do I have more than one"Trash" folder?