My ISP is blocking some of my ports, what can I do?

[admin]

This is a common problem that some of our customers experience, what to do depends on which ports are being blocked. If ports 110 (POP3), 143 (IMAP4), 389 (LDAP) or 8000 (WebMail) are being blocked then it is a simple matter of changing the port value and informing your users to use that port instead. However, if your ISP is blocking port 25 and you intend to receive mail from the Internet, you have a much bigger problem. SMTP must have port 25 and cannot just be changed. However, a company called No-IP have a ‘port redirection’ solution to this which allows you to change the port. For more information on No-IP’s service, please visit the No-IP site.