Re: [exim] Exim4 delay at boot

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Author: Jeremy Harris
Date:  
To: exim-users
Subject: Re: [exim] Exim4 delay at boot
On 13/11/2021 21:18, JHM via Exim-users wrote:
> On 13 Nov 2021 at 16:35, Jeremy Harris via Exim-users wrote:
>
>> On 13/11/2021 15:50, JHM via Exim-users wrote:
>>> IPv6 socket creation failed: Address family not supported by protocol
>
>> Inferring that the system as a whole has no ipv6 support would be a bit of a step.
> Unless, as is this specific case, all the necessary steps to disable IPv6 have been taken.
>
> See: https://lists.exim.org/lurker/message/20211112.211353.fde57a1f.en.html
>
> IPv6 is explicitly disabled on the host system at the kernel command line, at the /etc/hosts file
> and the /etc/ssh/ssh_config file.
>
> The virtual machine running the DNS on the host system is configured in the very same
> manner and the ADSL router also has it's IPv6 capacity administratively disabled.
>
> So, there's no IPv6 in the system or anywhere near it because I disabled it.
> No inferring so no step. <- just "taking the piss", so to speak. =^)


Wrong.

From that error return from that syscall, one would have to be making
an inference that the system had ipv6 disabled, to justify taking action
to not perform ipv6 actions in the rest of Exim. Exim doe not know
that there is no ipv6 in the system, nor that you disabled it.

>
> Exim makes a call when it starts up and sits there waiting to get an answer that it will not
> receive for the reasons stated above.
>
> Why does it do that?
>
> Because it installed with IPv6 enabled by default.


Actually because your configuration left it enabled.

>
> By adding a line to disable it in exim4.conf.template the problem was no longer a problem.
> The 30s delay was no more and I had no more /var/log/exim4/paniclog entries.
>
>> We could use some way of enquiring of the system ...
> Sure ...
>
> Check the kernel command line when installing and see if there's a ipv6.disable=1 stanza in
> it.
> That would be more than enough.


You can provide code to do this? Which still compiles cleanly on other
platforms? And the testing, added to the regression testsuite, to ensure
it carries on working into the future?

> Or ask at installation time if IPv6 should be enabled.


The Exim project does not install Exim into your system. The support
for doing that is provided by you distro - I think you said Devuan.
You need to go ask them for this feature to be added to their distro.
--
Cheers,
Jeremy