On 2019-04-13, Rainer Dorsch via Exim-users <exim-users@???> wrote: > Hi,
>
> I want to upgrade my server from Debian Jessie to Debian Stretch. I am afraid
> that at some time during the upgrade process, there is an invalid exim
> configuration and messages get rejected. In order to avoid that I was thinking
> of either redirecting via DNS to a server which does not listen to port 25 to
> enforce the sender to try again. Or redirect via DNS to a server which buffers
> all incoming messages until the Stretch setup is tested (not sure which server
> software does this though...).
>
> Can anybody recommend one of the approaches or even propose something
> better...?
Use iptables rules to block the public allowing only your tests to
reach exim.
If you have not editied any Debian conffiles the upgrade should proceed
smoothly with only a brief outage, no spurious rejects.
during the upgrade process a bad config is much more likely to prevent
exim from running than to cause spurious rejects.
I use Debian's split config wich allows me to separate my config
tweaks from the Debian provided conf files, this vastly reduces the
amount of editing needed during upgrades.
--
When I tried casting out nines I made a hash of it.
