<div dir="ltr">Hi John,<div><br></div><div>Thank you for the reply. Actually it was setup like this by another member, who left the team/company recently. Now it came to me to handle that responsibility. That's how I got in to this. At present I am not able to migrate/upgrade immediately. Because it sends emails around 100K+ emails everyday and I do not want to disturb that.</div><div><br></div><div>Coming back to your question, Actually the connection is : </div><div><br></div><div>O365/Outlook >> SMTP Gateway Server >> <a href="http://testing.test.com">testing.test.com</a> >> 2 POP3 servers.</div><div><br></div><div>Actually "<a href="http://testing.test.com">testing.test.com</a>", that is FQDN name set in F5 load balancer, where it is having the 2 POP3 servers to route the emails. </div><div>When the email was sent from Outlook/O365, first it goes to SMTP Gateway Server. Now the SMTP Gateway server has the postfix rule to send it to "<a href="http://testing.test.com">testing.test.com</a>". In this location, I am getting the error in SMTP Gateway Server, where it is not able connect (
lost connection with <a href="http://testing.test.com/" rel="noreferrer" target="_blank">testing.test.com</a> [xxx.xxx.xxx.xxx] while receiving the initial server greeting). </div><div><br></div><div>In SMTP Gateway server, instead of "<a href="http://testing.test.com">testing.test.com</a>", if i give the name/ip of any POP3 server, then email delivery is happening successfully to that POP3 server. The above error is coming only when i use the fqdn "<a href="http://testing.test.com">testing.test.com</a>", instead of direct POP3 server. </div><div><br></div><div>Please let me know if you need any more details. Could you please help me here.</div><div><br></div><div>Thanks,</div><div>Kishore Potnuru</div><div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Apr 23, 2020 at 7:13 PM John Stoffel <<a href="mailto:john@stoffel.org">john@stoffel.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">>>>>> "Kishore" == Kishore Potnuru <<a href="mailto:kishore.reachme@gmail.com" target="_blank">kishore.reachme@gmail.com</a>> writes:<br>
<br>
Kishore> I have the dovecot version 2.0.9 installed on RHEL linux 6.10<br>
Kishore> version. It's a single/standalone Live server. <br>
<br>
You should really upgradr your setup. <br>
<br>
Kishore> Now I have created another server with the same configuration<br>
Kishore> for the resilince purpose. I also tested and I am able to<br>
Kishore> send the emails to both of the dovecot servers<br>
Kishore> separately/individually. They are working fine.<br>
<br>
Dovecot doesn't do the mailing between systems, so i assume you've got<br>
postfix configured? And do you have shared storage behind your two<br>
dovecot instances so that your users don't have to login to multiple<br>
systems to get emails?<br>
<br>
Did you read the docs at:<br>
<br>
<a href="https://doc.dovecot.org/admin_manual/dovecot_cluster_architecture/" rel="noreferrer" target="_blank">https://doc.dovecot.org/admin_manual/dovecot_cluster_architecture/</a> <br>
<br>
Kishore> Now I have added those two servers under a F5 load balancer<br>
Kishore> and created a FQDN (example: <a href="http://testing.test.com" rel="noreferrer" target="_blank">testing.test.com</a>). I changed the<br>
Kishore> rules to send the traffic to FQDN "<a href="http://testing.test.com" rel="noreferrer" target="_blank">testing.test.com</a>", where<br>
Kishore> it should redirect the email to one of those 2 servers.<br>
<br>
So how is your F5 configured to work when one server is down? <br>
<br>
Kishore> When I sent the email to FQDN "<a href="http://testing.test.com" rel="noreferrer" target="_blank">testing.test.com</a>", I am getting the below error.<br>
<br>
Kishore> pf1_inbd/smtp[30292]: 66A5F5F6: to=<<a href="mailto:xxxxx@yyy.com" target="_blank">xxxxx@yyy.com</a>>,<br>
Kishore> relay=<a href="http://testing.test.com" rel="noreferrer" target="_blank">testing.test.com</a>[xxx.xxx.xxx.xxx]:25, delay=13,<br>
Kishore> delays=0.09/0.08/13/0, dsn=4.4.2, status=deferred (lost<br>
Kishore> connection with <a href="http://testing.test.com" rel="noreferrer" target="_blank">testing.test.com</a> [xxx.xxx.xxx.xxx] while<br>
Kishore> receiving the initial server greeting)<br>
<br>
Kishore> Could you please let me know how to fix this issue? It's a great help for me.<br>
<br>
Sounds like you haven't actually setup your system correctly. But<br>
we're not going to be able to help until you provide more details.<br>
It's also not clear from the about log file *which* server gave you<br>
this error.<br>
<br>
It would be smarted to start from scratch with an upto date install of<br>
dovecot (and postfix in my opinion) according to the Dovecot docs<br>
above, and test that out in a test environment. Then you would use<br>
'doveadm' sync to migrate user accounts over to the new system.<br>
<br>
John<br>
<br>
<br>
</blockquote></div>