From MozillaZine Knowledge Base
Thunderbird mail is organized using a profile manager, profiles, accounts, servers, identities, folders and SMTP servers. These terms can be confusing for two reasons:
This article explains these basic concepts of Thunderbird mail in some detail. If you do not need to know all the detail, then you can use the diagrams to see how things are organized.
The profile manager
The Profile Manager is a dialog that you can use to manage profiles and to choose which profile to use when Thunderbird starts up. One of the profiles is the default, which is used when you start Thunderbird without specifying any particular profile.
Thunderbird does not display the profile manager unless you request it, but conceptually the Profile Manager is the top of a hierarchy of containers used by Thunderbird to structure the way you work with mail:
Note: Technically, the profile manager represents data in the file profiles.ini, which is stored in a standard location on your computer.
A profile in Thunderbird contains all the information that you can work with in Thunderbird at one time. This information includes such things as the settings that you have entered in the program, themes and extensions that you have installed, the contents of your address books, and the sizes of windows and panes in the user interface.
A profile also contains accounts for receiving mail, and other kinds of account for other purposes. This article is only concerned with mail accounts.
Use more than one profile when you want to keep different sets of information completely separate. For example, if several people share the same computer, they can use separate profiles to keep their mail completely separate.
Do not use separate profiles for information that you want to work with at the same time. For example, if you sometimes want to work with business mail and personal mail at the same time, do not use separate profiles for them.
For the purposes of this article, a profile is simply a container for accounts (even though it really contains many other things):
A mail account specifies a server for receiving mail, and one or more identities for sending mail. It always has one default identity for sending mail, and it can include extra identities:
Use more than one account when you want to receive mail from more than one server (but note that Thunderbird uses the term server in a special way, explained below). For example, if you receive some of your mail from Gmail and some of your mail from the company you work for, then you need two accounts in Thunderbird.
Do not use more than one account for mail that is received from the same place. For example, if you have two e-mail addresses, and mail from both addresses is forwarded to the same POP3 server account, then use only one account to receive all the mail in Thunderbird.
Note: Technically, an account in Thunderbird is a collection of preference settings in your profile.
To see the settings for an account, use the Account Settings dialog.
Each mail account has eight* pages in the account settings dialog. Some of these pages are settings for the account's server, and some are for the account's default identity:
* The Junk Settings page is new in Thunderbird 2.
To work with settings for the account's identities, press the Manage Identities... button on the account's main page. Settings for the default identity are duplicated in this part of the user interface.
Note: When you press the Manage Identities... button and change settings there for the default identity, bug 373573 can prevent the Outgoing Server (SMTP) setting from transferring back to the main Account Settings page. To work around this, use the main Account Settings page to change this setting.
A server in Thunderbird is a collection of settings for receiving mail from a real mail server, perhaps together with folders for storing mail. A Thunderbird server is defined by three things:
When you create a new account in Thunderbird, at least one of these three things must normally distinguish its server from your existing servers in the same profile.
In Thunderbird, each account has one server, and each server belongs to one account. So the reasons for using more than one server, or not, are the same as for accounts in the section above.
More than one server in Thunderbird can specify the same real server. For example, your mail provider's POP3 server is mail.example.net, and you have two separate login names there: alfHome and alfWork. In Thunderbird you have two accounts and two servers, even though they both connect to: mail.example.net Note that this only applies to separate login names—it has nothing to do with your e-mail addresses.
When a Thunderbird server receives mail, it does not care what e-mail addresses the mail was sent to. If you receive mail that was sent to many e-mail addresses, you do not need to specify those addresses anywhere in Thunderbird. (If you want to send mail from many e-mail addresses, then add them as identities, which are described in the next section.)
A server can can store mail in the dummy account Local Folders, or it can have its own folders for storing mail:
An identity in Thunderbird is a collection of settings for sending mail. An identity is defined by:
Note: Technically, an identity in Thunderbird is a collection of preference settings in your profile.
Thunderbird allows you to create identities that look exactly the same, but if you do that you might find them confusing to use.
Use more than one identity when you want to send mail using more than one From name or e-mail address, or more than one SMTP server, or more than one signature, or more than one choice for any of the settings that Thunderbird provides in identities.
Thunderbird requires you to create a separate default identity for each account, but you can make these identities look exactly the same if you want to. For example, you receive some of your mail from Gmail and some of your mail from the company you work for, but you always want to send mail using your company From address. In your Thunderbird Gmail account, change the default identity to specify exactly the same details as in your work account.
If you receive mail that was originally sent to more than one e-mail address, then you might find it convenient to create identities for all those e-mail addresses. Then you can reply to a message from the same address that it was originally sent to.
Do not use more than one identity when one of your accounts already has an identity that you can use. This is because when you write a message you can change the From address to any identity from any account. There is usually no point in having duplicate identities in different accounts (unless they are default identities).
An identity specifies:
Settings for composing messages
Settings for composing messages only apply when you first start to write a message. If you choose a different From address after you start to write the message, then Thunderbird does not change these settings.
These settings are on the Composition & Addressing page, in the Composition area there. The settings for an account's default identity are on the account's Composition & Addressing page. To work with the settings for all the account's identities (including its default identity), press the account's Manage Identities... button.
When you write a new message, Thunderbird uses the account that is currently selected to determine the default identity to use. If no account (or the dummy account Local Folders) is currently selected, then Thunderbird uses the default account's default identity.
When you reply to a message, Thunderbird uses the account that is currently selected to find an identity that matches the address the message was sent to. If it cannot match the address, it uses the account's default identity. If no account (or the dummy account Local Folders) is currently selected, then Thunderbird uses the default account's default identity.
For example, your account's default identity specifies "Compose messages in HTML format", but another identity does not. When you write a new message, Thunderbird uses your default identity's settings and you see the HTML editor. When you reply to a message that was sent to your other identity, Thunderbird uses that other identity's settings and you see the plain text editor. While you are writing the message, you can change your From address, but doing this does not change the type of editor.
Settings for sending messages
Settings for sending messages apply when you send or save a message. If you choose a different identity as your From address after you start to write the message, then Thunderbird uses that new identity when you send or save the message.
Some of these settings are:
For example, you have two identites that specify different signatures. When you write a new message, you see your default identity's signature. When you change your From address to the other identity, Thunderbird changes your signature to that other identity's signature.
Folders contain messages. Depending on the server's type and settings, Thunderbird might only store part of each message, or only a reference to each message on the server. Even so, when you look in a folder Thunderbird shows you messages:
Note: A folder in Thunderbird is not the same as a folder (directory) in your local file system. Technically, Thunderbird uses a file in your local file system to store messages, another file to index them, and optionally a directory for subfolders.
An SMTP server is for sending mail. Thunderbird stores SMTP servers in a master list that can be used by identities in every account. One of the SMTP servers in the master list is designated the default:
Outgoing Servers (SMTP)
To work with the master list of SMTP servers, go to the bottom of the Account Settings dialog, below all the accounts, to the page: Outgoing Servers (SMTP)
Every identity in every account specifies either a specific SMTP server in the master list, or the default SMTP server.
Use more than one SMTP server when you want messages to be delivered by different routes. For example, if the company that you work for requires company e-mail to be routed through company systems, but does not allow personal e-mail to use those systems, then you must set up two SMTP servers in Thunderbird.
Do not use more than one SMTP server just because you have more than one account. It is usually simpler to use one SMTP server for all your identities in all your accounts, if the server and your network connection allow you to do that.
Switching SMTP servers
If you often have to switch SMTP servers, perhaps because you have problems accessing certain servers from certain networks, then:
There are also extensions that can help you to switch SMTP servers.