Disable IPv6?

[Lew Wolfgang]

Hi Folks,

It appears that a recent update on openSuSE has changed Thunderbird's behavior
with respect to IPv6. We're seeing long imaps connection times where it looks
like TB is trying to connect via v6, then falls back to v4 after what seems to be
several minutes. This is TB 45.4.0.

Is there a way to disable v6 in Thunderbird? I know it can be done in Firefox. It
would be nice if it could be disabled on a per-imap server basis.

BTW, even though we can get the dovecot server listening on v6, we'd still rather
not use it due to issues with rogue router advertisements coming from misconfigured
Windows systems.

Thanks,
Lew

[Keith Nuttle]

Try this site

http://www.techtin.com/browser/how-to-enable-ipv6-in-firefox/

[Lew Wolfgang]

On 11/07/2016 01:12 PM, Keith Nuttle wrote:
> On 11/07/2016 3:49 PM, Lew Wolfgang wrote:

> Try this site
>
> http://www.techtin.com/browser/how-to-enable-ipv6-in-firefox/

Thanks for the link, Keith. While it was about Firefox it had this link:

https://lists.fedoraproject.org/pipermail/users/2010-January/364063.html

That led me to:

Edit>Preferences>Advanced>General

which has a button for the config editor. I toggled this entry:

network.dns.disableIPv6; from false to true and that seems to take
care of the problem!

It's global for all sites, but that will do for now.

Thanks,
Lew

[Mark12547]

In article <mailman.638.1478551795.16819.support-
thund...@lists.mozilla.org>, wolf...@sweet-haven.com says...

> Is there a way to disable v6 in Thunderbird? I know it can be done
> in Firefox. It
> would be nice if it could be disabled on a per-imap server basis.
>

One would need to get into the configuration editor. In Thunderbird
45.4.0 under Windows 7, this is by going into Tools -> Options (or click
on the three horizontal lines -> Options -> Options), and on the Options
screen, "Advanced" tab, "General" subtab, in the lower right corner is
the button, "Config Editor..."

There are three options that may be of interest:

network.http.fast-fallback-to-IPv4 boolean
If the value is set to True, this allows Thunderbird to use IPv4 if an
IPv6 request isn't returned in a brief period of time. On my system it
appears that the default value is True, but it might not be the same for
your system, depending on add-ons or past changes.

Anyway if network.http.fast-fallback-to-IPv4 True does not work for you,
there are two more options that may help.

network.dns.ipv4OnlyDomains string
This is a comma-delimited list of domains. (Actually, each substring in
network.dns.ipv4OnlyDomains is compared with the rightmost part of the
host name, so network.dns.ipv4OnlyDomains value .doubleclick.net would,
for example, match server ad.doubleclick.net

I am not sure if it is a comma-delimited list (abc.com,def.com), or
comma space delimited list (abc.com, def.com).

Anyway, if you edit network.dns.ipv4OnlyDomains and type in the mail
servers that should NOT use IPv6, separating the server names with
commas, this should prevent Thunderbird from using IPv6 with those
specific mail servers.

network.dns.disableIPv6 boolean (default: false)
If you set network.dns.disableIPv6 to True, Thunderbird should use IPv4
for all servers.

Note: changes to any of these three configuration parameters would
likely require shutting down Thunderbird and starting Thunderbird back
up for them to take effect.

[Lew Wolfgang]

On 11/07/2016 02:07 PM, Mark12547 wrote:
> In article <mailman.638.1478551795.16819.support-
> thund...@lists.mozilla.org>, wolf...@sweet-haven.com says...

>> Is there a way to disable v6 in Thunderbird? I know it can be done
>> in Firefox. It
>> would be nice if it could be disabled on a per-imap server basis.
>>

Perfect Mark! This is exactly what we needed. A single comma seems to work as the delimiter.

Thanks,
Lew