This appears to have been resolved. The support guy added the 'our-domain-name.l.google.com' to the domains list and added their MX records to the delivery details. I've just sent a test message and have not received a delivery failure notification. I had not realised we could add this domain and specify a different delivery address.

<P>Hi</P> <P>We use the latest version of Mercury/32 on a Windows 2008 64bit Server.</P> <P>We have recently changed our mail filtering provider to Proofpoint.</P> <P>I had a global mail filtering rule set up that was configured so that mail received for <A href="mailto:happy.joe@domain.com">happy.joe@domain.com</A> is forwarded to <A href="mailto:happy.joe@gmail.com">happy.joe@gmail.com</A></P> <P>Because Proofpoint have accepted and delivered the message for happy.joe to our server, when the rule forwards that same message back out again to gmail.com, Proofpoint regards this as relaying and refuses to accept delivery of the message and gives a 554 5.7.1 relaying denied DSN:</P> <P>08:18:41.409: --- 18 Apr 2016, 8:18:41.409 --- 08:18:41.411: Connect to 'outbound-eu1.ppe-hosted.com', timeout 60 seconds. 08:18:42.449: >> 220 mx2-eu1.ppe-hosted.com - Welcome to Proofpoint Essentials ESMTP Server<cr><lf> 08:18:42.450: << EHLO domain.com<cr><lf> 08:18:42.493: >> 250-mx2-eu1.ppe-hosted.com<cr><lf> 08:18:42.494: >> 250-PIPELINING<cr><lf> 08:18:42.495: >> 250-SIZE 1024000000<cr><lf> 08:18:42.496: >> 250-ETRN<cr><lf> 08:18:42.497: >> 250-STARTTLS<cr><lf> 08:18:42.498: >> 250-ENHANCEDSTATUSCODES<cr><lf> 08:18:42.499: >> 250-8BITMIME<cr><lf> 08:18:42.500: >> 250 DSN<cr><lf> 08:18:42.503: << MAIL FROM:<<A href="mailto:smiling.fred@giggles.com">smiling.fred@giggles.com</A>> SIZE=34519<cr><lf> 08:18:42.545: >> 250 2.1.0 Ok<cr><lf> 08:18:42.546: << RCPT TO:<<A href="mailto:happy.joe@gmail.com%3E%3Ccr%3E%3Clf">happy.joe@gmail.com><cr><lf</A>> 08:18:42.608: >> 554 5.7.1 <<A href="mailto:happy.joe@gmail.com">happy.joe@gmail.com</A>>: Relay access denied<cr><lf> 08:18:42.612: << QUIT<cr><lf> 08:18:42.654: >> 221 2.0.0 Bye<cr><lf> 08:18:42.655: --- Connection closed normally at 18 Apr 2016, 8:18:42.655. --- 08:18:42.656: </P> <P>I have asked about this and our support guy has said that the only way around this is to deliver mail destined to the gmail address via a different host. We presently use MercuryC which has Proofpoint's address defined as the smarthost.</P> <P>This is proving to be a problem. The person concerned can't get their phone to connect via IMAP to our server (everyone else can), and they really need access to these messages when away from the office.</P> <P>I've not thought this through properly, but a solution may be to set up another instance of Mercury/32 on a different server, configure it with the same account details - <A href="mailto:happy.joe@domain.com">happy.joe@domain.com</A>, and set up MercuryE (end to end delivery). The forwarding rule on the original server can forward messages to happy joe on the second server which can then forward the messages to happy joe's gmail account via MercuryE. However, the original server would try to send the messages via the Proofpoint smarthost. Can Mercury/32 be configured to recognise another 'local' server and be configured to deliver selected messages to it?</P> <P>Anyone done this? Can anyone think of another (better) way to do this, please?</P> <P>Thanks</P>

<p>already tried <a href="http://support.proofpointessentials.com/index.php?/Knowledgebase/Article/View/202/0/how-to-whitelist-an-ip-address-to-bypass-spam-filtering-in-proofpoint-essentials" target="_blank" mce_href="http://support.proofpointessentials.com/index.php?/Knowledgebase/Article/View/202/0/how-to-whitelist-an-ip-address-to-bypass-spam-filtering-in-proofpoint-essentials">http://support.proofpointessentials.com/index.php?/Knowledgebase/Article/View/202/0/how-to-whitelist-an-ip-address-to-bypass-spam-filtering-in-proofpoint-essentials</a> ?</p><p>if yes and it didn't work: it is the bloody job of PP support to  make your setup work (e.g. to whitelist your address for relaying). You pay them == you make them solve your issues.</p><p> </p><p>Regards, Rainer </p>

Thanks for the link. That How-To seems to apply to inbound messages. I'll speak to our support guy and ask if we can whitelist outbound messages addressed to the gmail account.