I have setup zimbra and it relays external mail properly.
But the issue is as follows:
If zimbra user email@example.com sends to
another zimbra account, say to firstname.lastname@example.org,
I want it to route via the external server say mail.example1.com for some processing (encryption etc.) which will then route it back to the zimbra user email@example.com. Unfortunately, it does local delivery of all existing zimbra accounts without using the relay mta.
I tried to do as explained below, but it relays only non-local mails.
Transport Table for external servers - Zimbra :: Wiki
I also came across this posts, but it seems that they could not get it solved.
[SOLVED] How can I relay ALL mails (even internal ones)
split domain and sole use of mta relay
Could anybody please help me out with this?
I am using ZCS5.0.10 on CentOS.
Thank you very much in advance.