Failover delivery not working as expected

[w4tzmann]

Hello,

I would like to implement the following for outgoing emails:

1. Delivery directly via MX
2. If 1. does not work, then via SMTP2GO as a relay

As far as I can see, this scenario should be mapped with failover delivery: https://stalw.art/docs/mta/outbound/routing#failover-delivery

However, every outgoing email is now being redirected via the relay.
If I delete the smtp2go line, the emails are delivered directly. (Except to Deutsche Telekom, which does not like my IP address)

In the log (info level), I only see the email being sent via smtp2go, but no failed attempt before that, which should exist before the failover:

Does anyone have any idea where the error is?

Thanks!

[mdecimus]

Hi,

The screenshot is a bit blurry but it looks like your expression is between quotes, which is treated as a string.
Also note that the outbound strategy you are using will work only if the MX returns a temporary error. If the MX returns a permanent error delivery will fail and SMTP2GO won't be used.

[w4tzmann]

Hi,
Thank you very much for your repsonse.
Without the quotation marks, the mx entry takes effect again.
Is it possible to redirect Stalwart to the fallback (SMTP2GO) even in the event of a permanent error?

Alternatively, it would also help me if all emails sent to an MX entry with “t-online.de” in the name were redirected.

Telekom rejects my email as follows:

queueId = 293283568178709231, queueName = "remote", from = "postmaster@xx.xxx", to = ["xxxx@t-online.de"], size = 1243, total = 1, to = "xxx@t-online.de", hostname = "mx02.t-online.de", details = "Unexpected response for : Code: 554, Enhanced code: 0.0.0, Message: IP=XXX.XX.XXX.XX - None/bad reputation. Ask your postmaster for help or to contact tobr@rx.t-online.de for reset. (NOWL)", total = 0

Unfortunately, the postmasters there have there own rules and understanding of mail security...

[danielcolquitt]

Retrying via a relay on a 5xy error is definitely against the spirit of the relevant RFCs and probably also against the letter (depending at which space the rejection comes).

You can however route all messages to a particular domain through a relay using a Relay Delivery routing strategy.

[w4tzmann]

Telekom blocks large blocks of IP ranges and then creates its own rules to maintain a whitelist, which also goes against the spirit of mailing. They don’t care about SPF, DKIM, DMARC, etc.
I don’t want to use a relay server for all emails. Other mail servers/gateways allow me to configure settings more flexibly, so I can use the fallback mechanism, including 4XX and/or 5XX errors. It would be great if stalwart allowed the same.