Hi,
Dňa Sat, 13 Nov 2021 20:07:36 -0300 JHM via Exim-users
<exim-users@???> napísal:
> Hello:
>
> On 13 Nov 2021 at 22:09, Jeremy Harris via Exim-users wrote:
>
> > > So, there's no IPv6 in the system or anywhere near it because I
> > > disabled it.
> I must insist on this:
> IPv6 is explicitly disabled on the host, the virtual machine and the
> ADSL router. *I* disabled it.
We live in 2021, IPv6 is reality and important part of countries are
using it [1] (except my one :-P ) and most of nowadays OS enables it by
default for long time.
I meet IPv6 problem a long ago, and i still use one server (currently
debian oldstable) which has IPv6 disabled by default. But it has IPv6
disabled only due historical reasons from time when i had problem with
DNS A/AAAA queries (more than 10 years ago) and i do only minimal
required setting changes at upgrade on it. It is intended only for
intranet services (DNS cache, LDAP, etc) and has exim too, which acts
as LAN smarthost... And AFAIK, most (if not all) of that LAN computers
(and servers) has IPv6 support enabled. It works with IPv4 only
Internet access and it works for hundreds users and nobody complains (i
am employer's admin).
On Linux, there are multiple was how to deal with IPv6, it can be built
in kernel (where mentioned boot option is to disable it), but it can be
loaded as module too, where not loading it is enough to disable IPv6.
Even with buil-in support, it can be disabled in /proc FS and again no
cmdline is needed. In other words, detecting boot parameter can be
enough for OP, but it is not universal and better option approach
exist. BTW, there is 10 years old bug report about missing IPv6 and
exim in debian [2] & [3], and some info and links are in [4] too.
Nowadays i consider to disable IPv6 support as bad practice. i have no
DNS problems, even with software not supporting IPv6, nor to get AAAA
responses, nor to deal with IPv6 communication, except with services
which provides AAAA, but does not respond on it (but that is another
story). IPv6 autoconfiguration works fain, even in IPv4 only networks
and modern software can properly deal with it in that setup...
I consider as normal behavior to expect that IPv6 support is enabled in
system in present days in default configuration, as it is enabled by
default in OS. If someone does non default things, one have to do
it in software too and do not expect, that someone other will do his
home work.
The debian (and thus devuan too) is distribution intended for
experienced Linux admins and it is not intended to provide defaults
which works in all cases, nor which works in best manner (and in same
rare cases nor which works at all :-D) It is expected, that admins will
customize services to fit his own needing. If that doesn't work for OP,
perhaps it is not best distribution for he/she.
regards
[1]
https://www.google.com/intl/en/ipv6/statistics.html#tab=per-country-ipv6-adoption
[2]
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=610918
[3]
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=999612
[4]
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=747324
--
Slavko
https://www.slavino.sk
