I'm analyzing my logfiles after a test of sending live messages from Postini to my newly-configured SMTP gateway. Upon checking out the log, I see things like this: 64.18.2.90 - psmtp.com [12/Mar/2009:23:21:13 -0800] "EHLO -? psmtp.com SMTP" 250 243 64.18.2.90 - psmtp.com [12/Mar/2009:23:21:13 -0800] "STARTTLS - SMTP" 220 0 64.18.2.90 - psmtp.com [12/Mar/2009:23:21:13 -0800] "STARTTLS - SMTP" 220 29 64.18.2.90 - psmtp.com [12/Mar/2009:23:21:13 -0800] "HELO -? psmtp.com SMTP" 250 68 64.18.2.90 - psmtp.com [12/Mar/2009:23:21:13 -0800] "MAIL -? FROM:<> SMTP" 250 48 64.18.2.90 - psmtp.com [12/Mar/2009:23:21:13 -0800] "RCPT -? TO:<twsnider@ourdomain.com> SMTP" 250 52 64.18.2.90 - psmtp.com [12/Mar/2009:23:21:14 -0800] "QUIT -?psmtp.com SMTP" 240 92 64.18.2.108 - psmtp.com [12/Mar/2009:23:21:19 -0800] "EHLO -? psmtp.com SMTP" 250 244 64.18.2.108 - psmtp.com [12/Mar/2009:23:21:19 -0800] "STARTTLS - SMTP" 220 0 64.18.2.108 - psmtp.com [12/Mar/2009:23:21:19 -0800] "STARTTLS - SMTP" 220 29 64.18.2.108 - psmtp.com [12/Mar/2009:23:21:19 -0800] "HELO -? psmtp.com SMTP" 250 69 64.18.2.108 - psmtp.com [12/Mar/2009:23:21:19 -0800] "MAIL -? FROM:<coupons@berryacorn.com> SMTP" 250 68 64.18.2.108 - psmtp.com [12/Mar/2009:23:21:19 -0800] "RCPT -? TO:<slshupe@ourdomain.com> SMTP" 250 51 64.18.2.108 - psmtp.com [12/Mar/2009:23:21:19 -0800] "QUIT -?psmtp.com SMTP" 240 92 It quits directly after the RCPT line. I check the user's inbox, and the message never arrives. Postini didn't try to send it later, either. This is our biggest problem holding us back from switching to my new SMTP gateway. It doesn't do it to all messages, only about half or so. I thought it was an address space problem, but it has had no problems when it receives a mail on that IP address that is destined for a recipient that doesn't match the one in the address space - it just passes it to the SMTP connector that does. Any suggestions or help?

Software/Hardware used: