Your message dated Sat, 13 Nov 2021 18:09:08 +0100
with message-id <YY/xNNuvxp6wx/y...@argenau.bebt.de>
and subject line Re: Bug#999612: exim 4.94.5 installation configures IPv6 by
default on IPv4 only machines
has caused the Debian Bug report #999612,
regarding exim 4.94.5 installation configures IPv6 by default on IPv4 only
machines
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
(NB: If you are a system administrator and have no idea what this
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immediately.)
--
999612: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=999612
Debian Bug Tracking System
Contact ow...@bugs.debian.org with problems
--- Begin Message ---
Package: exim4
Version: 4.94.5
Severity: grave
On installation, Exim 4.94.5 will enable IPv6 *by default*, ignoring
several mechanisms in place to explicitly disable IPv6:
1.
A kernel command line explicitly disabling ipv6:
[code]
ipv6.disable=1
[/code]
2.
An /etc/hosts file with no machine readable IPv6 lines:
[code]
user@chuck:~$ cat /etc/hosts
#
127.0.0.1 localhost debian
#
# remmed to disable ip6
#::1 localhost ip6-localhost ip6-loopback
#fe00::0 ip6-localnet
#fe00::0 ip6-mcastprefix
#fe02::1 ip6-allnodes
#fe02::1 ip6-allrouters
user@chuck:~$
[/code]
3.
An /etc/ssh/ssh_config file explicitly disabling ipv6:
[code]
user@chuck:~$ cat /etc/ssh/ssh_config
--- snip ---
AddressFamily inet # instead of 'any' or 'inet6'
--- snip ---
user@chuck:~$
[/code]
This in turn creates this paniclog message:
[code]
IPv6 socket creation failed: Address family not supported by protocol
[/code]
On a machine with a DNS server (Unbound) running on a VBox virtual
machine which is also explicitly configured disable IPv6, there will
also be a rather annoying 30s delay at boot time.
This seems to be due to Exim talking directly to the DNS resolver
which will not answer AAAA queries as the machine it runs on is not
configured to use IPv6.
After waiting for 30s, Exim will continue loading.
This can be avoided by adding this line to the 'Main' section of
exim4.conf.template:
[code]
disable_ipv6 = true
[/code]
Once update-exim4.conf is run and the machine reboots, the delay has
gone away and there is no paniclog message.
To reproduce the problem, rolling back the edit of the
exim4.conf.template will bring back the 30s delay and the paniclog
message.
At the very least, add the disable_ipv6 = true (or false) to the
exim4.conf.template file, with the proper comments so that the issue
will not be hard to fix.
I had to add the line, it was not there by default in any of its
possible variants:
ie: disable_ipv6 = true ; disable_ipv6 = false ; disable_ipv6 =
The *best* solution would be to have the installer check for the
existence of the ipv6.disable=1 stanza in the kernel command line and
then ask for IPv6 confirmation if the line is not there.
A very small portion of the web runs on IPv6 and it will be some
years before IPv6 becomes the default option.
Thanks in advance.
--- End Message ---
--- Begin Message ---
Control: severity 999612 wishlist
On 2021-11-13 sawb...@xsmail.com wrote:
> Package: exim4
> Version: 4.94.5
> Severity: grave
> On installation, Exim 4.94.5 will enable IPv6 *by default*, ignoring
> several mechanisms in place to explicitly disable IPv6:
> 1.
> A kernel command line explicitly disabling ipv6:
> [code]
> ipv6.disable=1
> [/code]
> 2.
> An /etc/hosts file with no machine readable IPv6 lines:
> [code]
> user@chuck:~$ cat /etc/hosts
> #
> 127.0.0.1 localhost debian
> #
> # remmed to disable ip6
> #::1 localhost ip6-localhost ip6-loopback
[...]
Closing.
Well, you are running an unsupported setup.
cu Andreas
--- End Message ---
