Bug 530670

This bug appears to have been reported against 'rawhide' during the Fedora 12 development cycle.
Changing version to '12'.

More information and reason for this action is here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping

I've been testing a bit more.  Sometimes, but not always, is the RDNSS-announced nameservers added to the resolv.conf file.  I have not yet found out what exactly happens when it works and what happens when it don't...

Tore

I think I've nailed it.  If the kernel is performing SLAAC at the same time as NM is activating an interface, and NM has the IPv6 mode set to "automatic", the IPv6 nameservers are added to /etc/resolv.conf.  If you then disconnect from the network and reconnect, the connection fails completely (because the SLAAC address is removed by NM as the connection is taken down, see bug #530669 - that bug seems very closely related to this one).  You can however work around this by forcing the kernel to re-do SLAAC ("ip link set dev wlan0 down; ip link set dev wlan0 up" while NM is disconnected does the trick for me).

However, if you first connected to the network using IPv6 mode "ignore", then disconnect, change to "automatic" and then reconnect, it will successfully reconnect but _NOT_ add the IPv6 nameservers to /etc/resolv.conf.  I assume this is because when NM is in "ignore" mode it will not remove the SLAAC-configured address when it's disconnecing, so when it reconnects with mode automatic, the already-configured address is enough to make the "automatic" mode not fail, but since SLAAC isn't performed at that point, NM does't pick up the nameservers.

It seems like the kernel will only perform SLAAC automatically when the interface looses its NO-CARRIER flag for the first time after having been set to UP.  So one workaround would be for NM to down/up the interface when it's disconnecting/reconnecting, or to somehow explicitly tell the kernel to perform SLAAC again when it's reconnecting.

Tore

Thanks for the analysis, I'll dig into this more and see what we can do to make this work better.

NetworkManager-0.8.0-8.git20100426.fc13 has been submitted as an update for Fedora 13.
http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-8.git20100426.fc13

NetworkManager-0.8.0-8.git20100426.fc12 has been submitted as an update for Fedora 12.
http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-8.git20100426.fc12

NetworkManager-0.8.0-8.git20100426.fc13 has been pushed to the Fedora 13 testing repository.  If problems still persist, please make note of it in this bug report.
 If you want to test the update, you can install it with 
 su -c 'yum --enablerepo=updates-testing update NetworkManager'.  You can provide feedback for this update here: http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-8.git20100426.fc13

NetworkManager-0.8.0-8.git20100426.fc12 has been pushed to the Fedora 12 testing repository.  If problems still persist, please make note of it in this bug report.
 If you want to test the update, you can install it with 
 su -c 'yum --enablerepo=updates-testing update NetworkManager'.  You can provide feedback for this update here: http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-8.git20100426.fc12

NetworkManager-0.8.0-9.git20100429.fc13 has been pushed to the Fedora 13 testing repository.  If problems still persist, please make note of it in this bug report.
 If you want to test the update, you can install it with 
 su -c 'yum --enablerepo=updates-testing update NetworkManager'.  You can provide feedback for this update here: http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-9.git20100429.fc13

This appears to be 99.99% fixed by NetworkManager-0.8.0-10.git20100502.fc12.x86_64. During my testing, I only once saw NM not add my RDNSS configuration to /etc/resolv.conf. Every other time, it's worked.

https://admin.fedoraproject.org/updates/NetworkManager-0.8.0-11.git20100503.fc13
https://admin.fedoraproject.org/updates/NetworkManager-0.8.0-11.git20100503.fc12

If you're still having problems, please give these a try.

NetworkManager-0.8.0-11.git20100503.fc13 has been pushed to the Fedora 13 testing repository.  If problems still persist, please make note of it in this bug report.
 If you want to test the update, you can install it with 
 su -c 'yum --enablerepo=updates-testing update NetworkManager'.  You can provide feedback for this update here: http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-11.git20100503.fc13

NetworkManager-0.8.0-11.git20100503.fc12 has been pushed to the Fedora 12 testing repository.  If problems still persist, please make note of it in this bug report.
 If you want to test the update, you can install it with 
 su -c 'yum --enablerepo=updates-testing update NetworkManager'.  You can provide feedback for this update here: http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-11.git20100503.fc12

NetworkManager-0.8.0-11.git20100503.fc13 has been pushed to the Fedora 13 stable repository.  If problems still persist, please make note of it in this bug report.

NetworkManager-0.8.0-12.git20100504.fc13 has been submitted as an update for Fedora 13.
http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-12.git20100504.fc13

NetworkManager-0.8.0-12.git20100504.fc12 has been submitted as an update for Fedora 12.
http://admin.fedoraproject.org/updates/NetworkManager-0.8.0-12.git20100504.fc12

NetworkManager-0.8.0-12.git20100504.fc13 has been pushed to the Fedora 13 stable repository.  If problems still persist, please make note of it in this bug report.

NetworkManager-0.8.1-0.1.git20100510.fc12 has been submitted as an update for Fedora 12.
http://admin.fedoraproject.org/updates/NetworkManager-0.8.1-0.1.git20100510.fc12

NetworkManager-0.8.1-0.1.git20100510.fc12 has been pushed to the Fedora 12 stable repository.  If problems still persist, please make note of it in this bug report.