Duke Mailing List Manager

Sympa Help


  1. Welcome
  2. Sympa Terminology
  3. Web Interface Overview
    1. Main Menu Items
    2. User Menus
      1. Login/User Information
      2. Your Lists
      3. List Overview
      4. List Operations
  4. Frequently Asked Questions
    1. General Questions
      1. How do I create a new mailing list?
      2. How do I search a list's archives?
      3. How does Sympa know what my email address is when I log in with my NetID?
      4. I changed my preferred email address and now I can't see any of my lists. Why not?
      5. What commands are available for the email interface?
      6. Why can't I post to a subscribers-only list to which I'm subscribed?
      7. How can I subscribe to a list?
      8. How can I unsubscribe myself from a list?
      9. Is there a limit to the number of subscribers that can be on a list?
    2. List Owner Questions
      1. What's the best way to add subscribers to my new list?
      2. How do I add or remove a list Owner?
      3. How do I add or remove a Moderator/Editor?
      4. How do I add a bunch of subscribers at once?
      5. How do I change the list's info file?
      6. What are all these options for sending, receiving, subscribing, etc?
    3. List Moderator Questions
    4. List Subscriber Questions
  5. Other Sites and Links


The Sympa mailing list manager has a web interface called WWSympa, providing you access to the mailing lists and your subscriptions.

Using WWSympa, you can search for and view various mailing lists, manage the lists you're subscribed to, manage lists you own or are a moderator of, and a small host of other functions.

These help documents are intended to provide you with general instructions and direction in finding your way through the complex and powerful capabilities that the WWSympa web interface offers you. If you have any questions or concerns, including any comments (both constructive and critical) about the help files or web interface, please submit a request to the Duke OIT Help Desk via an email to help@oit.duke.edu.

Sympa Terminology

Here are some commonly used terms in Sympa, WWSympa, and mailing lists in general along with their definitions.


Sympa is a piece of software called a mailing list manager. It provides a mailing list service on a host, allowing groups of people to communicate with one another via email without having to know who all the members of the group are and all their individual addresses.


Sympa's web interface is referred to as WWSympa, though sometimes the term "Sympa" can refer to both the web interface and the rest of the Sympa software running behind the scenes together. WWSympa provides you with a clean, easy to use interface with which you can manage your lists and subscriptions.

Mailing List

A mailing list, often referred to with the shorthand "list," is a means of sending electronic mail to many different addresses at once. The sender does not need to know the addresses of everyone on the list in order to ensure that the mail gets to all of them.

Of course, regular electronic mail may be sent to multiple addresses. However, a mailing list is superior to this approach in several ways. In the multiple-address approach, each person who wants to send to the entire list must know all of the addresses on the list. Since there is a need for the list of addresses to be kept in many places, it may be difficult to keep all of the lists the same. For example, suppose that Alex, Betty, Charlie, and Darlene write mail to each other regularly. Later, if they wish to include Earnest in their group, then each of the first four must know that Earnest has been added and they must all know his email address.

When you send mail to a mailing list, you address the mail to the mailing list's name. When the mailing list server receives the message, it expands the name of the mailing list into each of the individual addresses currently on the list and it redirects your message to each of those people, called subscribers. Then, should the membership of the list change, there is only one file containing the addresses of the subscribers which must be updated.

Mailing lists can alternately be referred to by their name or their address; a list's name is everything before the @ sign in its address.


The listmasters are the system administrators and help desk personnel who actually manage and maintain the Sympa system. A listmaster is the one who installed the Sympa software running on this host and is the one responsible for its functionality, as well as any site-specific modifications that have been made to better suit the needs of this site's users.

If you need to reach the listmasters, please submit a request via an email to help@oit.duke.edu.

List Owner and Privileged Owner

Often referred to as simply an "owner," a list Owner is a person who has nearly full control over a list. They are the list's stewards, bouncers, mothers or fathers, and benevolent dictators. They handle all subscription and unsubscription requests, along with managing the list's settings and permisssions. Both owners and privileged owners are the same thing in terms of what they can do with the list, but we have a policy requiring that there only be one privileged owner per list, and that person must be affiliated with Duke University. In the event that multiple list owners want different, conflicting settings for the list, we turn to the privileged owner for the final word. Other than that, there are no differences in what either the privileged owner or regular owners can do. Also note that non-Duke people can be designated as list owners, but not privileged owners.

Note: A list owner, privileged or otherwise, does not necessarily need to be subscribed to a list. ownership and subscription are separate things, and if you are a list's owner you may wish to subscribe yourself to it or you will not see any of the messages which get sent to the list.

Also note: All list owners are automatically subscribed to the sympa-announce mailing list. This is so that we can keep list owners up-to-date with any Sympa issues or announcements, including updates, news, outage notifications, etc.

To reach a list's owners, send an email to LISTNAME-request@duke.edu, replacing LISTNAME with the list's actual name (e.g. to reach the owners of the bluedevils@duke.edu mailing list, send an email to bluedevils-request@duke.edu).


Used interchangably with the term "editor," a list moderator is someone whose job it is to approve or decline messages sent to moderated lists.

Often a list will be set to only allow specific people to post and require everyone else to be moderated, or it will simply require everyone's posts to be moderated. This means when a user sends a message to the list it doesn't go out to the list's subscribers straight away. Instead, it enters a holding queue and a moderator is notified. They then view the message, determine if its content is appropriate to the list, and either approve it or deny it based on that decision. On high-volume lists, several moderators may be in place to help lighten each one's individual load.

Note: Like ownership, being a moderator does not necessarily mean you're a subscriber. If you are a list moderator and you wish to see postings to the list then you must explicitly subscribe yourself to the list, or have a list owner do it for you.

To contact a list's moderators, send an email to LISTNAME-editor@duke.edu, replacing LISTNAME with the actual list's name (e.g. to reach the moderators of the bluedevils@duke.edu mailing list, send an email to bluedevils-editor@duke.edu).


A list's subscribers are all the people who are on the list and likely should receive a message that gets sent to the list; in practice this is not always the case as some users' addresses are invalid, or the list may be moderated and thus the message won't go straight to the list, or they may have their preferences set to not receive mail from a given list. Subscribers make up the bulk of users of a system, and as each list has many subscribers each subscriber can be on many lists. Some lists are set up such that anyone who's interested can look at the list's homepage and click a link to become a subscriber, whereas others require the owner's approval before being allowed on the list, and still others have different ways for getting their bundle of subscribers.

Some lists will also let anyone post, and some are set to only allow subscribers to post, regardless of whether the list is moderated or not.

To contact the subscribers for a list, assuming you are allowed to do so, simply send a message to LISTNAME@duke.edu, replacing LISTNAME with the actual name of the list (e.g. to send mail to the bluedevils list, address a message to bluedevils@duke.edu).


Normally a mailing list will send all messages to its subscribers as it receives them, and users will then receive the individual messages at various times throughout the day. For some users, or in some cases, this is less than desirable — it can interrupt your workflow, can cause you to get far more email than you'd like, and can just generally be annoying. Some people prefer to get their messages in what's called a digest, where the mailing list gathers up all the messages over a span of time (usually one day) and then sends them out as a single bundle to subscribers who've elected to only receive digests. This allows them to read through the mail (or ignore it entirely) at a more leisurely pace.

Sympa supports two types of digests: multi-part MIME digests and regular plain-text digests. For most people the former will work, where Sympa sends you a digest made of multiple messages in a specialized mail format called MIME, but older email clients may not support that and for those users we recommend the plain-text digest, where Sympa just compiles all the messages in the digest into one text message and sends that out.

List Info File

Each list has an "info file," which contains basic information about the list. This file is sent to people on request, as well as in the welcome message sent out to new subscribers. The list owner controls its content.

Generally a list owner will want to include such information in the info file as what the list is for and what it's about, appropriate posting guidelines and restrictions, information on who the owners are, etc. Basically anything that you'd want a new subscriber to know.

List owners can change the list's info file via the following menu choices in the List Operations menu: List Administration → Edit Message Templates → choose "list description" in the drop-down menu and click the Edit File button.

List Subject

Not to be confused with the subject of a message sent to the list, the list's subject is a brief, one-line description about the list. Basically, it should describe the list as best it can in one sentence.

List owners can change the list's subject by choosing the following menu items in the List Operations menu: List Administration → Edit List Configuration → List Definition.

Shared Document Library

Some lists have a shared document library, where list members or owners (depending on the list's configuration) can post files for other list members. This is far better than simply sending out an attachment to the list for many reasons, including that it doesn't use exponentially more space on the mail server for each copy of the attachment, it doesn't trigger any message size limits on mail servers, and users can access it any time they want, even if they weren't on the list when it was originally sent out.

Web Interface Overview

WWSympa uses a common look across all its pages, so familiarizing yourself with the general layout of the system will allow you to more easily use all of its functions.

Main Menu Items

Along the top of the page, just beneath the main title, is the main WWSympa menu. It contains the following links:


This link will take you to the main page.

On the main page, you'll see a welcome and overview message, along with a list of the categories of mailing lists available on the system. Each list is organized into one or more categories, and you can browse for lists which might interest you through these links.

You may also search for a list by name.

Request a List

If you're a member of the Duke University community (i.e. your email address ends in “duke.edu”) then you should see a link to request a new list creation. It will take you to a form you can fill out requesting a new mailing list.

Index of Lists

This link will take you to a listing of all the publicly viewable lists that are hosted at this site. Note that if a list of yours is not displayed and you'd like it to be, odds are that it's set to be a hidden or concealed list. Check the list options help for more information.


This link takes you to the page you're currently reading, with help information that applies to the entire WWSympa site and the Sympa mailing list manager in general.

User Menus

Along the left side of the page are the user menus, the precise contents of which change based on what you're currently looking at or doing in WWSympa.

Login/User Information

Starting at the top is the login or user menu; if you're not logged in you'll see a place to input your user name and password, along with links to either send yourself a reminder of your password or create a new account so you can login and manage your subscriptions.

If you are logged in, you'll see the email address of the account with which you're logged in, which is where mail will be sent when you subscribe to a list, a link allowing you to manage your Preferences and a link letting you logout. You may also see, when looking at a list, your role listed just below your email address — this describes your current role with regard to the list you're looking at and thus what privileges and access levels you'll have.

Your Lists

Beneath the user or login menu is the "Your Lists" menu. Here are all the lists to which you're subscribed or of which you are an owner.

For each list which you either subscribe to or own an entry will be shown here with a link to take you to the list's homepage; if you are a list owner then you'll also have a link called "Owner" that will take you to the list's administration page. Note: because of the separation between being a list owner and being a subscriber, if you're an owner you'll see the list here regardless of whether or not you're subscribed to it. Check the list's subscribers to see if you're on it to find out if you're subscribed, if you're unsure.

List Overview

If you're looking at a list's page, include its homepage, then the Your Lists menu will be replaced with one giving you an overview of the list's basic information, including:

List Name
This is the list's name, which also happens to be the left-hand side (everything before the @) of its address.
List Address
The list's address. Sending an email to this address will, depending on the list's configuration, send it to everyone on the list.
List Subject
The brief, one-line description of what the list is about. The list's purpose summarized into one or two sentences.

How many subscribers are on the list. If you're one of the list's owners then you'll also see how many of those addresses are bouncing or refusing mail.

If the list is configured to allow you to see who all the subscribers are then the word "Subscribers" in this menu item will be a link to the page where you can browse or search for subscribers of the list.

Owners/Email the list owners
If you're an owner of a list, here you'll see displayed all of the list's owners. Regular users will instead see a link to email the list's owners.
Moderators/Email the list moderators
If you're the owner of a list and the list has any moderators, here you'll see displayed all of the list's moderators. Regular users will instead see a link to email the list's moderators.
List Operations

If you're looking at one of a list's pages, including its homepage, then you will see the List Operations menu. Its options allow you to view the list's homepage, subscribe to or unsubscribe from the list, change your subscription options if you are a subscriber, access the list's archives or shared documents, and a few other choices. More information about these menu options follows:

List Home
Takes you to the list's homepage.
List Administration
Shown only to list owners, this link will take you to the list administration section where you can change various parameters of the list's configuration, alter and update different list templates, manage subscribers, and perform other functions related to managing the list.
List Moderation
Shown only to list moderators and owners, beneath it are three sub-items allowing a list moderator or owner to access currently pending message, document, or subscription requests.

If you're not already subscribed to the list, this link will either add you as a subscriber (if the list is set to allow anyone to subscribe) or dispatch a request to the list owners asking them to either approve or decline your subscription.

If there is no Subscribe link shown in the List Operations menu then it means subscription to this list is closed and you can only be added by the owner manually adding you.

Subscription Options
If you are a subscriber then the Subscribe link will be replaced with Subscription Options where you can change some aspects of your subscription to the list.
If you're subscribed to a list you'll have this link in your List Operations menu. You may use it to unsubscribe from the list.
Post to List
If you are allowed to post messages to the list then this link will take you to a page where you can compose an email to be sent to the list.
List Archives
If the list has archives of messages that have been sent to it and you have the appropriate privileges to view the archives then this link will take you to a page where you can browse through or search the list's archives.
Shared Documents
If the list has a shared document library and you have access to it you'll see a link here which will take you to the file browser.

Frequently Asked Questions

Here are various frequently asked questions or commonly seen problems that people have about or with Sympa and WWSympa. If you have any questions not covered here, please let the Sympa Listmasters know.

General Questions

How do I create a new mailing list?

First, new mailing lists can only be requested by members of the Duke University community. You must be logged in with your duke.edu email account, and if you are then you should see a link in the main navigation bar near the top of the page entitled "Request a List." Clicking it will take you to the new list request form. Fill out all the fields on that form, and if you need any help then click the "Help" link at the top of that page, next to where it says "Request a New Mailing List."

How do I search a list's archives?

When you're viewing a page for a list, and assuming the list has archives and the owner has it set to allow you to access them, you'll see a link in the "List Operations" section along the left hand side to access the "List Archives."

On the list's archive page, you'll see a simple search box in the upper right corner of the page. Input the text you want to search for and click the "Search" button.

For more advanced searches, click the "Advanced Search" button beneath the search text input field.

How does Sympa know what my email address is when I log in with my NetID?

Sympa looks up your preferred email address from the Duke online directory. Whenever you subscribe to a mailing list, Sympa will use this address to add your subscription to the list. Sympa also uses it to determine which lists you're on and whether not you're an owner or moderator of any lists.

If you are not receiving any messages from any lists you're subscribed to in Sympa, it's possible that this address is incorrect or is forwarding to an account you're not checking — for instance, mail may be getting forwarded from firstname.lastname@duke.edu to netid@duke.edu and you use and regularly check a departmental account or Notes account. If this is the case you will want to change where this address points. If you visit the Online@Duke e-mail alias management page then you can click the "Change my e-mail alias" link and be taken to another page where you can set the "EMAIL ADDRESS" to be your preferred email account (i.e. your departmental account, continuing our example from above). Note: Changes made to your alias can take up to 24 hours to process.

If you have any questions or problems with this, then please submit a request to the Help Desk at help@oit.duke.edu.

I changed my preferred email address and now I can't see any of my lists. Why not?

Unfortunately this is a drawback with how Sympa currently works. If you change your preferred email address in the Duke online directory, then Sympa will no longer recognize you as being subscribed to, owner of, or moderator of any of your previous lists. A Sympa listmaster will have to go through and update your subscriptions, so please submit a request to the Help Desk at help@oit.duke.edu. Include in that help request both your old and new preferred email address. We apologize for any inconvenience this may have caused.

What commands are available for the email interface?

You can run some commands and operations with Sympa through the “email interface.” By sending a message to sympa@duke.edu with nothing in the body but the word HELP you'll be sent a help guide that covers how to run commands via email.

Please make sure you're either sending out plain-text messages, or are including minimal formatting (no special fonts or colors and no images) in any rich-text messages. If you have trouble sending out plain-text messages with your email client and you're a member of the Duke community then you may wish to use the Duke University Webmail System for sending messages to sympa@duke.edu. Doing so shouldn't interfere with your regular email use, but if you have any questions or concerns please contact your departmental help desk or the central OIT Help Desk.

Why can't I post to a subscribers-only list to which I'm subscribed?

If your postings are being rejected by the list and returned to you, it's highly likely that you're posting using an address that's not on the list. Mail clients like Notes, Outlook, Thunderbird, or Mac OS X's Mail can be configureed to report a “From:” address — usually it's the address associated with the account, but some mail clients allow you to set up multiple or alternate “From:” addreses for one account. When you send mail using the client, it reports the message as being from the account's “From:” address. This is what Sympa checks to determine whether or not you're allowed to post to a list, for most lists configured to only allow subscribers or any other select group of people to post.

There are a handful of options for both list owners and list members to remedy these situations:

  1. Change your “From:” address.
  2. If you're a member of Duke's faculty or staff, change your preferred email address.
  3. Subscribe multiple addresses to the list and set them to not receive list mail.
  4. Have the list owner relax restrictions on who can send to the list.

Changing your “From:” address

Precise instructions for how to check or change your “From:” address are beyond the scope of this document, but there are instructions for the most commonly used and supported mail clients on the OIT Help Desk's site.

If you're a Gmail user, here are instructions for changing your “From:” address.

Changing your preferred email address

Duke faculty and staff can change the email address that's reported for them in the directory using Online@Duke. Here is a direct link to the page allowing you to change your directory listing. Simply change the field for “Preferred email address for publication in the directory” near the top of that page and click the “Submit” button down near the bottom to save the changes.

NOTE: Directory updates may be delayed by a few hours and in order to see your list subscriptions you'll have to submit a request to the Duke OIT Help Desk. Let us know you've changed your preferred email address, what you changed it from and to, and that you need us to make the appropriate updates in Sympa so you can see your lists. We'll then go through and update Sympa with your new address, and all of your lists should again be visible to you.

Subscribing multiple addresses to the list

On most lists, you can subscribe multiple addresses to the list and tell the list to only send you mail at one of them. Note that some lists may require owner approval for you to subscribe, or may even require the owner themselves to subscribe you. For most lists, however, the following should do the trick. From the account with which you wish to be able to send messages to the list, send an email to sympa@duke.edu with the following in the body:


Replace LISTNAME in the above with the list's name. Once you've received the list's welcome message — note, again, that it may take some time for the list's owner to approve your subscription request — then send another message to the same address with the following in the body:


Again, replace LISTNAME with the name of the list. This will set this address to not receive list messages, so you won't receive multiople copies of messages sent to all the addresses with which you're subscribed.

Have the list owner make the list more open

If privacy on the list isn't the number one concern — especially if it's outranked by convenience and/or ease of use for list members — then the list owner can set the list up to be less restrictive of who can post to it. They can read this FAQ entry on list authorization scenarios for more information about the different options.

How can I subscribe to a list?

You can either visit the list's home page at <https://lists.duke.edu/sympa/info/LISTNAME> (replacing LISTNAME with the list's name), or you can send a message to sympa@duke.edu with either the subject or body:


Again, replace LISTNAME with the list's name.

If you run into any problems subscribing yourself to the list, please contact the list's owners at <LISTNAME-request@duke.edu> (still replacing LISTNAME with the name of the list).

How can I unsubscribe myself from a list?

If you're on a mailing list and wish to be removed from it, you have a couple of choices. If you're on the list with the email address that shows up under "Email Address" in the "User Information" section after you log in, you can simply click the list's link under "Your Lists," and then hit the "Unsubscribe" link under "List Operations."

If you don't see the list under "Your Lists" then you're probably subscribed under a different address, and you'll need to use the email interface to remove that address from the list. Simply send a message to sympa@duke.edu with the following in either the subject or the body:


Replace LISTNAME with the name of the list and ADDRESS with the address you want removed. For Duke users, this is almost always going to be your netid@duke.edu address. You will then be sent a confirmation message by Sympa to which you can simply reply.

If you run into any problems removing yourself from the list, please contact the list's owners at <LISTNAME-request@duke.edu> (replacing LISTNAME with the name of the list).

Is there a limit to the number of subscribers that can be on a list?

While there is no practical limit — some of our lists have tens of thousands of members, and there are lists at other Sympa sites with hundreds of thousands — the more subscribers there are on a list, the longer it's going to take for messages to go through, and the harder it can become to manage list members. But, if you have a need for a very large list, Sympa should be able to handle it.

List Owner Questions

What's the best way to add subscribers to my new list?

Once your list has been approved, you're left with the task of filling it with the right people. Under older systems like Majordomo, you'd simply add a bunch of email addresses to the list and hope that they were valid and correct. With Sympa, especially because of its integration with the Duke online directory, this isn't always the best way — for instance, if you added a user to the list as netid@duke.edu and their preferred email address as listed in the Duke directory is firstname.lastname@duke.edu then when they log in with their NetID they won't see their subscription (see this FAQ entry on “From:” addresses for more info). With Sympa, the best way to invite users to join a list is to do just that — invite them. There are two ways to do this.

You can either use the email interface and send an email to sympa@duke.edu with the following in the body of the message:


Replace LISTNAME with the mailing list's name and EMAIL with the user's email address in the above. You may repeat that line for multiple users, substituting a different EMAIL for each user. Alternatively, you can simply send out a normal email using whatever email client you prefer to your intended subscribers, inviting them to visit a URL similar to the following:


Replace LISTNAME in the above with the actual mailing list's name. When users visit that link they'll be asked to log in with either their NetID (for Duke users) or an email address (for non-Duke users). Once they've logged in, their subscription request is submitted and either automatically approved or submitted to the list owners for approval, depending on that specific list's configuration.

Using these methods to add users to a list, rather than inputting many addresses, means that they're able to subscribe with their primary email address, thus making it easier for them to use the Sympa system and to change where their mail is routed in the future.

Note: Users may have additional problems with their email client not being configured to properly report the address that Sympa recognizes as theirs, and thus rejecting their messages to the list. Please refer them to this FAQ entry on posting and “From:” addresses for more information.

How do I add or remove a list owner?

At the present time the only way to add an owner to your list is to send an email to sympa-request@duke.edu and ask the Listmasters to add or remove them; please provide the name and email address(es) of the owners and whether you'd like us to add or remove them, in that message.

Note: Policy dictates that only members of the Duke community (faculty, staff, students, etc.) may be Privileged Owners of lists. This is to maintain a degree of verifiability when it comes to tracking down who is actually responsible for the list, its members, and contents.

How do I add or remove a moderator/editor?

Adding or removing a list moderator requires you be the owner of the list. From the list's home page, click “List Administration” in the “List Operations” menu section, along the left side of the page. Then click “Edit List Configuration,” and finally click “List Definition.”

Scrolling down, you should see a section beginning with “Moderators.” Here are all the moderators of the list, along with an empty set of entry fields with which you can add new ones. To add a new moderator, simply fill out the empty fields before “Moderators defined in an external datasource” section. Only the email address is required, though you may want to put their name in so that users see it instead of their address. The “private information” field is for whatever information you'd like to put in there, such as a telephone number, and is only visible to other list owners. Removing a moderator is simply a matter of deleting their email address, name, and private information.

Once you've made your changes, scroll down to the bottom of the page and click the “Update List Configuration” button to save the new settings.

How do I add a bunch of subscribers at once?

If you've got a list of subscribers' addresses and you'd like to add them all in one go, that's a fairly simple process. Assuming you've got the appropriate privileges to add subscribers to a list and you're looking at any of the list's pages, including its homepage, simply click the "Subscribers" link in the "List Overview" menu section along the left side of the page. From the "Manage Subscribers" page, click the "Bulk Add Addresses" link.

On the "Bulk Add Addresses" page you'll see a text box with some example addresses and names in it. Replace the contents of this text box with the addresses, one per line, of the users you wish to subscribe to the list. You may follow an address with a space and the user's real name if you so choose. When you're done, you may check the "Don't send welcome message" option to prevent sending the new subscribers any notification or welcome message when they're added to the list; while users generally prefer to receive the welcome message, in some cases it may not be desirable such as if you're migrating users from an old list. Then simply click the "Add Subscribers" button and you're all set.

How do I change the list's info file?

Only a list's owner may change the info fileFrom the list's homepage (or any page for the list, really), click "List Administration" in the "List Options" section, along the left side of the page. From there, click "Edit Message Templates." From the drop-down menu select "list description" and click the "Edit File" button.

You'll be presented with the file editor, where you can make the changes to the description. When you're done click the "Save Changes" button to commit the changes you've made, or if you'd like to revert the file to the way it was when you began editing it.

What are all these options for sending, receiving, subscribing, etc?

Sympa uses “authorization scenarios” (or just “scenarios”) to determine whether or not a given user can perform a given action. Some examples for when scenarios are used (and what the class of that scenario is called) are:

  • Sending messages to lists (send)
  • Subscribing to a list (subscribe)
  • Unsubscribing from a list (unsubscribe)
  • Whether or not the list is shown in the main index of lists (visibility)
  • Requesting a new list (create_list)
  • Viewing who's subscribed to a list (review)
There are different choices available for each class of scenario. Below you'll find more verbose descriptions about what some of the available choices do, as well as how to change which scenario is being used.

Sending Scenarios

To change which send scenario is being used for your list, select the list under “Your Lists,” then click “List Administration” in the “List Operations” section, then “Edit List Configuration,” and finally “Sending/Receiving Setup” — the send scenario choices are in the first section, named “Who can send messages.” Available choices include:

No one may send to the list. Pretty straightforward, if not necessarily widely useful. Can be handy if you need to temporarily shut off list traffic due to a rampant virus or overly aggressive spammer.
Anyone may send to the list, and their messages get flagged for moderation. List moderators may send straight to the list, unfettered by message approval queues.
Anyone may send to the list, and their messages get flagged for moderation. This even applies to moderators.
Anyone may send to the list, and their messages get flagged for moderation. List moderators, however, are sent back a confirmation request when they send messages to the list, asking them to confirm the message before it gets sent out.
Anyone whose address ends in “duke.edu” may send messages to the list.
Anyone whose address ends in “duke.edu” or anyone who's subscribed to the list may send messages. This can be useful for when you want a more open list without opening it up too widely for spammers, since most spammers don't use “duke.edu” addresses.
Only list moderators may send messages to the list. This is most useful for announcement-style lists, where you want a select group to be able to broadcast messages out to all the list members, without anyone else being able to contact the list.
Similar to the newsletter send scenario, this one only allows moderators to address the list, and it sends them back a confirmation message asking them to make sure they want to send that message to the list. Like newsletter with a safety net. It also prevents poeple from being able to falsify messages to the list by setting their mail client up to claim to be one of the moderators.
Only list owners and moderators may send messages to the list.
Only list owners, moderators, and subscribers may send messages to the list. This is the standard default for non-public lists as it prevents spammers and other such miscreants from getting messages out to the list. You may find that subscribers who try to send messages to the list with alterante addresses are having their messages rejected — check the Why can't I post to a subscribers-only list to which I'm subscribed? FAQ entry for more information about this.
Only list owners, moderators, and subscribers may send to the list, and they all require valid S/MIME signatures. S/MIME signatures are specialized attachments that verify, through the use of a trusted third party, the sender's identity as being authentic and the message as being unaltered. This is the most secure setting for your list, but all the users on the list must have valid S/MIME signatures.
Only subscribers and moderators may send messages to the list; those of the former must be moderated and those of the latter go straight through. Similar to the editorkey option, but only allowing subscribers to submit messages for approval rather than anyone.
Moderators can send straight through to the list, as can subscribers, but messages with attachments will be flagged for approval by a moderator.
Only subscribers may send to the list, and they will need to confirm every message by replying to a confirmation message Sympa sends them before the message will go through to the list.
Only subscribers and moderators may send to the list. They'll both be asked to confirm their messages, and subscribers' messages will get put into the moderation queue (moderators' messages will go straight out).
Subscribers and moderators may send messages straight out to the list. Non-subscribers' messages will be flagged for moderation. This can be useful for allowing users who are not subscribers to submit messages while still letting the moderators keep spam away from the list's population.
Subscribers may send messages to the list, as may users whose S/MIME signatures can be verified. Everyone else must confirm their messages by replying to a confirmation message Sympa sends them before the message gets resent on to the list. This is useful for reducing spam without increasing the list moderators' workload as spamming systems are usually automated and very, very rarely — if ever — are sophisticated enough or watched well enough to approve the message.
Anyone in the world may send to the list. This is really only suitable and recommended for contact addresses where there really is no other way to allow anyone who may need to send to the address the ability to do so.
Anyone may send to the list, but messages with Bcc (blind carbon copy) recipients are rejected. This can help prevent some spam, though most spammers no longer use Bcc headers for recipients.
Anyone may send to the list, provided they approve their own message by appropriately replying to the confirmation message Sympa sends them.
Anyone may send to the list. Messages with attachments are flagged for moderation.
Anyone may send to the list. Messages with attachments are simply rejected.

Other Sites and Links

Some sites related to this one, which you may find helpful and informative.

Main Sympa Site
The source for all things Sympa.
Sympa Mailing Lists
The Sympa team maintains and runs a few mailing lists related to Sympa and its development. The one which is likely to be most interesting to a user of a Sympa system would be the sympa-users list.