Hi thanks but I have already read this guide and configured the fortimail unit correctly, in fact all connections work.
As explained above the problem exists only for SMTP conections sent by the printers from the districts of my network.
(e.g. 192.168.X.0/24) while the connections coming from my network where the fortigate resides and where the VIP of my zimbra server is configured in DMZ, 192.168.0.X/24 are forwarded without problems.
The log of these sessions are identical except for the last mail event log on the fortimail unit:
- relay=[192.168.10.6] [192.168.10.6], dsn=2.0.0, stat=Sent (Ok: queued as BB6ACB2C0167) [192.168.0.73]
- relay=[192.168.10.6] [192.168.10.6], dsn=4.7.25, stat=Deferred: 450 4.7.25 Client host rejected: cannot find your hostname, [192.168.4.216]
This should be the roceived response from the Zimbra server, the strange thing is that without the fortimail unit the problem was not prensetava, analyzing the zimbra logs we see that the mails have in the HELO the unit name fortimail.example.it
In the zimbra admin panel I tried to add to the Authorized MTA networks other than the local one, but the server response to the fortimail unit is still the same.
From webmail everything passes, from client (outlook) everything passes, from internal network 192.168.0.X/24 everything passes, from network 192.168.X.0 and/or public Ip, only SMTP sessions get this response log.
As it is the situation should depend only on the ZIMBRA server, the fact is that before the instalation of Fortimail this problem was not there from the client side.
Miguel Sotomayor Gonzalez