I run it at home on dsl with dynamic IP using a ddns client. There is something happening now when I send email from the ispconfig server. I get an error of:
"it was not possible to send this e-mail
SMTP Error: Recipient not accepted. Verify your relay rules
This happens when trying to send to an email address out on the internet. It started doing this one or two days ago.
I used a tool to telnet to the ispconfig smtp port 25 and it was successful so I know it is open and not blocked.