Something changed in SMTP Proxy between 2.4.1 and 2.5.1???

[Guest]

[bernieL0max]

Have duplicated all settings from a 2.4.1 install to a new 2.5.1 install, including the SMTP Proxy settings, which have been checked & double-checked.  The old VM is switched off and the new VM has the same LAN IP.  Almost everything is functioning as expected; except that now my Exchange server is refusing to accept messages with the following error:

2012-03-26 13:39:28
postfix/smtpd[10724]: NOQUEUE: reject: RCPT from mail..net.au[...]: 450 4.1.1 <lhowlett@XXXXXXXXXXX.org>: Recipient address rejected: undeliverable address: host 10.36.1.2[10.36.1.2] said: 550 5.7.1 External client with IP address 10.36.1.254 does not have permissions to submit to this server. Visit http://support.microsoft.com/kb/928123 for more information. (in reply to MAIL FROM command); from=<alesha@XXXXXXXXXXX.org.au> to=<lhowlett@XXXXXXXXXXX.org> proto=ESMTP helo=<BGTHILSV-DC..net.au>

This is extremely frustrating!

[David.Dejaeghere]

Where do you see this error? in the maillog of endian or another postfix instance?
Which host is your endian vm and wich one is your mta?
10.36.1.254?
10.36.1.2?

I asume 10.36.1.254 is your endian and 10.36.1.2 is your MTA and you see this in the maillog from your mta?
Then it seems that your MTA does not allow endian to relay messages. This means the Endian its configuration is ok but not your MTA its configuration.
If you are using postfix as MTA please show us your main.cf