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On 09/24/2012 10:34 PM, Chris Gebhardt - VIRTBIZ Internet wrote:
<blockquote cite="mid:50612631.5000400@virtbiz.com" type="cite">
<pre wrap="">Michael Stauber wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi all,
Ok, this is indeed something funny and needs to be looked at.
I tried to make sense about the suggestions as to what needs fixed where
to disable IPv6 entirely.
</pre>
</blockquote>
<pre wrap="">
If it may please the court, may I submit we have IPv6 disabled by
default, but not completely removed... just in case we might like to
make some manual entries so that we could use IPv6 if desired?
We're actually doing this "on purpose" on a couple of boxes, and I have
another couple of customers who are also experimenting.
</pre>
<blockquote type="cite">
<pre wrap="">Can someone please summarize this again for me in one message? Thanks!
</pre>
</blockquote>
<pre wrap="">
Sure thing. One of my hosting boxes "magically" grabbed an IPv6 address
using auto discover. Sendmail attached to the IPv6 IP. Our nameservers
are all IPv6-enabled. This hosting box happened to look up the
mailserver for comcast.net:
mx1.comcast.net. 300 IN A 68.87.26.147
mx1.comcast.net. 48 IN AAAA 2001:558:fe14:70::22
mx2.comcast.net. 300 IN A 76.96.40.147
mx2.comcast.net. 7200 IN AAAA 2001:558:fe2d:70::22
dns101.comcast.net. 292 IN A 68.87.29.164
dns101.comcast.net. 292 IN AAAA 2001:558:1002:a:68:87:29:164
dns102.comcast.net. 3560 IN A 68.87.85.132
dns102.comcast.net. 3560 IN AAAA 2001:558:1004:7:68:87:85:132
dns103.comcast.net. 3560 IN A 68.87.76.228
dns103.comcast.net. 3560 IN AAAA 2001:558:1014:c:68:87:76:228
dns104.comcast.net. 3560 IN A 68.87.68.244
dns104.comcast.net. 3560 IN AAAA 2001:558:100a:5:68:87:68:244
dns105.comcast.net. 3560 IN A 68.87.72.244
dns105.comcast.net. 3560 IN AAAA 2001:558:100e:5:68:87:72:244
The box used one of the IPv6 records to connect to comcast.net. The
only problem here was that we did not have a proper PTR on the IPv6
address. We rectified that in all of about 2 minutes after noticing the
issue, and mail went through just fine.
So I suppose the issue is that for most production cases, it would be
best to have IPv6 disabled.
We happen to be making an aggressive IPv6 push, so I'm not going to be
one of the folks who says just eliminate all IPv6. But I do agree that
in most cases it would be best if left disabled by default.
This should be as simple as adding this to ifcfg-eth0:
IPV6_AUTOCONF=no
</pre>
</blockquote>
Also we found dovecot with and ipV6 issue<br>
<br>
fix was adding <br>
listen = *<br>
default is listen = ::, *<br>
/etc/dovecot/conf.d/10-master.conf<br>
<br>
without this fix dovecot would not start, errors, (all 3 different
protocols)<br>
<pre wrap=""><big>listen(::, 110) failed: Address family not supported by protocol</big>
</pre>
<br>
<div class="moz-signature">-- <br>
Gerald<br>
<br>
</div>
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