SMTP 554 5.7.1 with smarthost/relayhost

[Jeroen van Meeuwen (Kolab Systems)]

On 2012-05-02 14:35, Martin Campbell wrote:
> I am using Kolab with a smarthost/relayhost because my SMTP server 
> has a
> dynamic IP address. Some SMTP servers block dynamic IP addresses.
> Occasionally a recipient's SMTP server sends the following error 
> message
> to the smarthost/relayhost SMTP server (which is then forwarded back 
> to me).
> "SMTP protocol diagnostic: 554 5.7.1 This message has been blocked
> because the return email domain is invalid"
>
> Can anyone suggest a solution to this situation?

First things first: what is the domain part of the sender email 
address, does it have one or more publicly available IN A and/or MX DNS 
records?

Kind regards,

Jeroen van Meeuwen

-- 
Systems Architect, Kolab Systems AG

e: vanmeeuwen at kolabsys.com
m: +44 74 2516 3817
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