There are two ways to access Exchange emails through DavMail Gateway: the good old and efficient POP protocol, limited to Inbox access and the IMAP protocol that enables full message folder tree access. IMAP support in DavMail is more recent and less optimised than POP.
This page describes POP3 setup, if you need multiple folders access, proceed to IMAP Thunderbird mail setup instead.
DavMail can be used with any POP3/SMTP client by adjusting the following description designed for Thunderbird
Edit common name and Exchange mail address:
Choose POP as server type, located at localhost:
Populate in and out login names with Active Directory account name, i.e. domain\account with Exchange 2003 and earlier. You don't need the domain name prefix with Exchange 2007.
Edit account name (email address by default):
Finish:
Create a new outgoing mail configuration under account settings:
Server name is localhost, edit port according to DavMail settings. The connection must use authentication with Active Directory account and encryption is not needed.
Proceeed to Thunderbird calendar setup