Fwd: Load balancer for dovecot servers - Not able to send emails

[John Stoffel]

>>>>> "Kishore" == Kishore Potnuru <kishore.reachme at gmail.com> writes:

Kishore> I have the dovecot version 2.0.9 installed on RHEL linux 6.10
Kishore> version. It's a single/standalone Live server. 

You should really upgradr your setup.  

Kishore> Now I have created another server with the same configuration
Kishore> for the resilince purpose. I also tested and I am able to
Kishore> send the emails to both of the dovecot servers
Kishore> separately/individually.  They are working fine.

Dovecot doesn't do the mailing between systems, so i assume you've got
postfix configured?  And do you have shared storage behind your two
dovecot instances so that your users don't have to login to multiple
systems to get emails?

Did you read the docs at:

  https://doc.dovecot.org/admin_manual/dovecot_cluster_architecture/  

Kishore> Now I have added those two servers under a F5 load balancer
Kishore> and created a FQDN (example: testing.test.com). I changed the
Kishore> rules to send the traffic to FQDN "testing.test.com", where
Kishore> it should redirect the email to one of those 2 servers.

So how is your F5 configured to work when one server is down?  

Kishore> When I sent the email to FQDN "testing.test.com", I am getting the below error.

Kishore> pf1_inbd/smtp[30292]: 66A5F5F6: to=<xxxxx at yyy.com>,
Kishore> relay=testing.test.com[xxx.xxx.xxx.xxx]:25, delay=13,
Kishore> delays=0.09/0.08/13/0, dsn=4.4.2, status=deferred (lost
Kishore> connection with testing.test.com [xxx.xxx.xxx.xxx] while
Kishore> receiving the initial server greeting)

Kishore> Could you please let me know how to fix this issue? It's a great help for me.

Sounds like you haven't actually setup your system correctly.  But
we're not going to be able to help until you provide more details.
It's also not clear from the about log file *which* server gave you
this error.

It would be smarted to start from scratch with an upto date install of
dovecot (and postfix in my opinion) according to the Dovecot docs
above, and test that out in a test environment.  Then you would use
'doveadm' sync to migrate user accounts over to the new system.

John