ISPconfig3 on Lenny, using port 587 for smtp, but also tried 25 and 2525--all are open in the firewall. I'm using Thunderbird 3 portable on a usb key, so the settings don't change, and sending in Windows 7 works fine, but when I try to send mail in Windows XP I get connection failed. Also when I use an installation of Thunderbird 2 on Windows XP I get a connection error. Receiving mail works fine in both. I also tried to get a client's Outlook Express on Windows XP to send and that failed--had to set him up to use his isp's mail server to send. Any ideas? Also, should I disable imap?