Dear Sir/Madam, I followed Falko Timme's tutorial of "The Perfect Server - Ubuntu Karmic Koala (Ubuntu 9.10) [ISPConfig 2]" to setup the ISP web hosting system, ISPConfig 2 and Squirrelmail, but I have problem when testing the email (in ISPConfig 2, create client, website, user & mail for squirrelmail etc before testing the email): 1. in Ubuntu prompt, run "mail root" to send email message to my personal email address email@example.com, to email address firstname.lastname@example.org created in ISPConfig 2 for the user & mail. But the email message could neither be received from email@example.com nor firstname.lastname@example.org. 2. login into Squirrlemail webmail interface and sent email message to my personal email address email@example.com, but the email message couldn't be received from firstname.lastname@example.org as well. 3. from email@example.com, sent email message to firstname.lastname@example.org, but the email message couldn't be received in email@example.com. In all, the email message delivery into and out the email system hasn't been worked so far. It is much appreciated if anyone can help with this, e.g. the information guidance to identify and solve the problem; the approach to test each part/server in the email delivery chain to discover the issue; whatever helpful approach/method.