MTA keeps saying "no relaying allowed"

Question

Hi! 
 I'm quite new to SFOS 16 and after I've discovered, that Legacy SMTP seems to be broken ("Connection refused"), I've tried to implement the MTA mode but I didn't quite understand, how to configure this correctly. 
 In the past, I've used the SMTP rule to do spam/av-checking and while passing it down to my mail server. But when in MTA mode, my XG seems to check whether the incoming mail is really targeted to my domain. Does this involve maintaining a list of (valid) eMail accounts or domains within XG? 
 Sorry, maybe I'm missing the spot here ;-)

SaschaParis · Accepted Answer

Hello Oxident 
 I attach here a quick&dirty "guide" or "howto" to set up MTA 
 
 First you create the SMTP Policy 
 
 Check that in the device settings relaying is allowed for all zones where mail is incoming or outgoing. Usually this is WAN and LAN (or DMZ - wherever your Mailserver resides) 
 
 Check the autocreated firewall (Business) policy. Maybe change settings as WAN Interface to use in the NAT settings, IPS etc. 
 
 and finally configure relaying settings. Under hostbased relay you should enter your internal devices using XG as MTA/Smarthost. At least there should be entered your mailserver. You also may add some MFC printers, webservers and other devices capable of sending mails directly via XG. Under Upstream hosts you enter "ANY", if you receive mails directly from Internet, or the IP&acute;s from where mails arrive, if you use a upstream mail spooler.

That should basically do the job 
 
 Addendum few hrs. later concerning "Does this involve maintaining a list of (valid) eMail accounts or domains within XG?" 
 ==> No, not mail accounts, but mail domains. If you own (and want to receive mails for) the domain example.com, you have to enter this in the MTA routing section, so the MTA only accepts mails to that domain and will reject other domains.