Fast Folder Access
Folder access performance is greatly improved through the use of dbm (a simple
database provided by perl). When a mail folder is selected in the folder view,
Open WebMail will parse the mail folder file and cache the parsed result to a
dbm. This dbm is reused whenever the user wants to access the folder. The dbm
cache eliminates the scan of an entire folder for every access, a significant
benefit when dealing with a large folders. The dbm is automatically synchronized
with any changes to the folder itself; the dbm update is incremental if the
folder modification is done by the Open WebMail application itself.
The dbm will however be recreated when a folder is found to have been changed
by an external program.
Efficient Message Movement
The size of a message will be slightly increased after it is read at the first
time because of status change. A large movement of messages may be introduced
due to the size change. Also, the user may want to move a group of messages
between two folders. The routines for message update and movement have been
totally rewritten so that minimal movement occurs, with correspondingly minimal
memory utilization.
Smaller Memory Footprint
Much effort has been put into optimizing Open WebMail's memory utilization. The
memory footprint of Open WebMail is much smaller than its predecessors when
dealing with messages with large attachments (e.g. a 20MB document), as a result
of which the application now runs smoothly on a medium sized machine, (e.g. a
Celeron 300 with 128MB RAM).
Convenient Folder/Message Operation
Open WebMail supports 'create', 'rename', 'delete', and 'download' operations
on folders, and 'move', 'copy', 'delete' and 'download' operations on messages.
Graceful File Lock
Since a mail folder may be used by multiple programs simultaneously, it is
necessary to lock the file before accessing the folder. Open WebMail uses a
blocking lock with a timeout limit of 60 seconds. It gives the lock a better
chance of success than a nonblocking lock, which returns an error if the lock
can not be acquired immediately. Open WebMail also supports locking by dotlock
file to ensure that the file locking operates correctly on platforms operating
with an incomplete implementation of NFS lockd.
Remote SMTP Relaying
With the help of Net::SMTP module, openwebamil can talk SMTP to SMTP daemons
on either localhost or remote machine. This gives openwebmail the better
compatibility with various smtp daemons. The system administrator also has
more flexibility when designing the mail service system.
Virtual Hosting
You can have as many virtual domains as you want on same server with only one copy
of openwebmail installed. Open Webmail supports per domain config file.
Each domain can have its own set of configuration options, including domainname,
authentication module, quota limit, mailspooldir ...
You can even setup mail accounts for users without creating real unix accounts for them.
Please refer to Kevin Ellis's webpage:
"How to setup virtual users on Open WebMail using Postfix & vm-pop3d"
User Alias
Open Webmail can use the
sendmail virtusertable for user alias mapping.
The loginname typed by user may be pure name or name@somedomain. And this loginname
can be mapped to another pure name or name@otherdomain in the virtusertable.
This gives you the great flexibility in account management. For example,
you may have john for different domains by actually mapping them to
different real user ids.
john@domain1.com john1
john@domain2.com john2
john@domain3.com john3
Per User Capability Configuration
While options in system config file(openwebmail.conf) are applied to all users,
you may find it useful to set the options on per user basis sometimes.
For example, you may want to limit the client ip access for some users or limit
the domain which the user can sent to. This could be easily done with the per
user config file support in Open Webmail.
Various Authentication Modules
Various authentication modules are directly available for openwebmail,
including auth_unix.pl, auth_ldap.pl, auth_mysql.pl, auth_pgsql.pl and
auth_pop3.pl.
With these modules, openwebmail can be integrated with other systems easily.
PAM support
Openwebmail can also use other sources for authentication through the PAM
(pluggable authentication module). Ex: NIS+, NIS, LDAP, Radius.... Solaris 2.6,
Linux and FreeBSD 3.1 are known to support PAM.
For more information about PAM, please see
http://www.kernel.org/pub/linux/libs/pam/
Full Content Search
Full content search with regular expression support is provided. When a user
enters a keyword in the search box, the scope of the mail folder is limited
to the keyword related messages. This means the user can use the sort or
static functions on the search result. The scope limit is released when the
user selects another folder or refreshes the current folder.
Strong MIME Message Capability
Most webmail packages present MIME messages poorly compared to traditional
POP clients. Open Webmail presents MIME messages in an attractive format
comparable to that presented by Microsoft Outlook. It does this through
supporting unlimited levels of attachments and cid object cross-reference
inside attachments. Open WebMail also supports uuencoded block inside messages,
and displays those uuencoded blocks as if they were normal attachments.
Draft Folder Support
This feature enables the user to write a message in a number of stages,
even over several days. The user can save an unfinished message into the
draft folder and continue editing at any time.
Spelling Check Support
The spelling check in Open WebMail is very user-friendly and powerful:
It makes suggestions for mis-spelled words, and the user can correct the
errors very easily by selecting one of the suggestions from a drop-down menu.
POP3 Support
Multiple POP3 accounts can be defined, allowing a single user to fetch mails
from a number of mail servers. All messages fetched will be stored in the
INBOX folder. Should the fetch operation exceed 10 seconds (due to a slow
link or large message for example), the operation will be put into background
to avoid an http timeout.
Mail Filter Support
Multiple filter rules can be set to move or copy incoming mails to different
folders automatically or even delete them directly. The user can categorize
mails from a specific person or spammer, and identify mails containing viruses
very easily by defining rules of sender, receiver, SMTP relay, subject, body
or filename of attachments.
Since mail filtering is activated only in Open WebMail, messages will stay in
the INBOX until the user reads their mail with Open WebMail. 'finger' or other
mail status check utilities may report new mail incorrectly, since they are not
aware of filters: A command tool 'checkmail.pl' is provided for use as
finger replacement, which performs mail filtering before reporting mail status.
Message Count Preview
When the user pulls down the folderlist menu to select a folder, the counts of
new messages and total messages of each mail folder are displayed after the
folder name to assist the user in finding unread messages.
Confirm Reading Support
The user can request a 'confirm-reading receipt' for each message sent. When
the message is read by the recipient, a receipt will be sent back to this user.
There are too many other small enhancements to mention. You may choose to find
them by yourself...
