You have EXTERNAL domain listed in relay_domains? Don't do that.
For relaying to arbitrary remote sites, the SMTP client should be
in a trusted network (mynetworks), or the client should authenticate
(with SASL login, or TLS cert).
It was not clear from the anonymized description which was which.
Wietse
Adam Barnett:
> This was happening when sending internal to external so how can i populate
> relay_recipient_maps ?
>
> --
> ______________________
> Adam Barnett
> Systems Engineer
> Double Negative
> 160 Great Portland Street,W1W 5QA
> T: 020-7268-5000
> [ http://www.dneg.com/ | www.dneg.com ]
> ______________________
>
> ----- Original Message -----
> | From: "Wietse Venema" <[email protected]>
> | To: "Postfix users" <[email protected]>
> | Sent: Friday, 11 October, 2019 12:01:57
> | Subject: Re: Split Domain MTA relay access denied
>
> | ab:
> |> Hi
> |>
> |> Added the domain to $relay_domian but they i get this error
> |
> | Good.
> |
> |> Recipient address rejected: User unknown in relay recipient table;
> |
> | Populate relay_recipient_maps, or use recipient address verification.
> |
> | http://www.postfix.org/STANDARD_CONFIGURATION_README.html#backup
> | http://www.postfix.org/ADDRESS_VERIFICATION_README.html#recipient
> |
> | Background info:
> |
> | http://www.postfix.org/postconf.5.html#relay_recipient_maps
> | http://www.postfix.org/ADDRESS_CLASS_README.html
> |
> | Wietse
>