[plug] not able to send e-mail, but can recieve

[Jon Miller]

I'm experiencing a problem where I cannot send e-mail but I can receive mail.
In the /var/log/mail.log I have the following:
Oct 19 13:31:25 mail postfix/smtp[30902]: 6465E150052: to=<sb9a470c.073 at gateway.mmtnetworks.com.au>,                                                  relay=mx2.amnet.net.au[203.153.224.10], delay=386012, status=deferred (host mx2.amnet.net.au[203.153.224.10] said: 450 Client host rejected: cannot find your hostname, [203.153.242.19] (in reply to RCPT TO command))

I spoke to the ISP this morning, but this still has not cleared up.

My question is in the main.cf file do I have to relayhost = my isp or nothing.  They tell me that I'm sending mail through them but this isn't the case as the relayhost = is blank, which to my understanding means it sends the mail directly out.
All of this happened when Amcom started having issues last week.

Jon
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.plug.org.au/pipermail/plug/attachments/20051019/5399c030/attachment.htm>