Can I check that the Zimbra server is on a different internet connection to you? If no, how is it communicating on port 25?
Your ISP wont be blocking all port 25 traffic, just port 25 destined for anywhere other than it's own mail servers.
Try telnetting to smtp.yourisp.com or whatever it should be, on port 25; you should be able to connect. If you can, try the same excercise to the zimbra server, if that fails then you know it's an ISP limit and you should speak to them to ask for it to be lifted. |