I have installed ISPConfig3 188.8.131.52 on Ubu9.10 server using your Perfect Server install tutorial, running under VirtualBox on WindowsVista. Net interface is a bridge to 192.168.1.61. My external DNS (referenced in resolv.conf) has mapped: ubunsv61.postmarks.com to 192.168.1.61 u61.postmarks.com to <my comcast external ip> Router is port-forwarding all the necessary ports for Postfix, IMAP etc. to the 192.168.1.61 box, including an additional port (2500) for Postfix. I have been able to setup e-mail accounts on Squirrel mail, and successfully send and receive e-mail using the webmail interface. However, when I attempt to setup a local Thunderbird client with IMAP access, I'm getting 'imapd: LOGIN FAILED, user=[email protected] The hostname is mapped to the 192.168.1.61 IP, which is listed as mydestination in Postfix. The local 192.168.1.0 network is listed in mynetworks. I read one posting which suggested that there is a name prefix required (web1_mybox@<domain> for example), but I have no idea what 'web1' refers to. I'm not looking to access the /webmail interface from Thunderbird, I want to set it up as a local IMAP client, assuming ISPConfig3 allows that. I haven't been able to find any documentation specific to ISPConfig3, other than forum postings. I'm a bit confused as to the relationship between 'Clients', 'Resellers', 'Mailboxes', 'CP Users', and it appears that setting up a system user under Ubuntu creates problems for ISPConfig3 if the names are coincidentally the same. I just setup a new Squirrel mailbox, but I don't know where to look for the incoming mail. I'm also looking for some documentation of the relationship between the various MySQL tables and the Postfix configuration. I've already spent a day or so trying to get a basic IMAP server setup that can provide browser-based e-mail, concurrently with local Thunderbird clients, and don't seem to be getting anywhere. I'm sure I can get this to work if I go around ISPConfig, but I'd very much prefer to adopt this framework if I can find some technical documentation, even if it's in rough draft form. Any suggestions appreciated.