At first I cannot reproduce it. It happened 2-3 times. I have a wireless account in "manage connections". I happen to notice that after a router restart , NetworkManager reconnects to my wifi router, but only with IPV6 enabled. The bug is that on the connection settings I have IPV4, method:Automatic DHCP, and IPV6 method:disabled. Network manager gives me only IPV6 ip , and ignores the above configuration. As a result internet does not work (IPV4 ip missing). ifconfig output with the problem: wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet6 fe80::9200:4eff:fe91:99d3 prefixlen 64 scopeid 0x20<link> ether 90:00:4e:91:99:d3 txqueuelen 1000 (Ethernet) RX packets 136511 bytes 70689658 (67.4 MiB) .... ifconfig output that works fine: wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.1.2 netmask 255.255.255.0 broadcast 192.168.1.255 inet6 fe80::9200:4eff:fe91:99d3 prefixlen 64 scopeid 0x20<link> ether 90:00:4e:91:99:d3 txqueuelen 1000 (Ethernet) .... When it happens that, I get the same only IPV6 configuration, every time I disconnect or connect my wireless , and even I get the same after a restart. The only way to solve the problem, is to delete my "Manage Connections" account and create a new one. Reproducible: Couldn't Reproduce Actual Results: IPV6 enabled wifi without IPV4 ip, even when IPV6 is disabled in my account, and DHCP automatic in IPV4 Expected Results: IPV4 enabled internet wifi, that conforms with my account configuration, in NetworkManager.
Which Plasma NM version do you use? You can see the version string in "Manage Connections" -> "Other". Please, also send me the configuration file of your connection that you can find in /etc/NetworkManager/system-connections/<connection name>.
Version 0.9.0.5 (nm09 20121206) /etc/NetworkManager/system-connections/Mycon: [connection] id=Mycon uuid=1a91eb32-90b3-4fa9-a2df-1600f96b9c60 type=802-11-wireless zone= [802-11-wireless] ssid=Mycon mode=infrastructure security=802-11-wireless-security [802-11-wireless-security] key-mgmt=wpa-psk psk=****mypass*** [ipv4] method=auto may-fail=false [ipv6] method=ignore
The configuration looks ok to me, that must be something wrong in NetworkManager itself or your IPv4 dhcp server is taking too long to answer and NetworkManager is enabling IPv6 whant that happen. Which NetworkManager version do you use?
networkmanager 0.9.6.4-1 Maybe we put the bug on WAITINFO status, until it happens again , and I can post you some more info....
Which dhcp client do you use? I use dhcpcd and looking in my system's log I can see that dhcpcd requests IPv6 address even though I set my connection to ignore IPv6 in NetworkManager. So maybe this is a problem in your dhcp client configuration. If you use dhcpcd try adding "noipv6rs" to /etc/dhcpcd.conf.
dhclient: Internet Systems Consortium DHCP Client 4.2.4-P2
The main problem here is not that NetworkManager through dhclient asks for IPV6, the main problem is that it DOESN'T ask for normal 192.168.1.2 IPV4 ip, so I don't have internet, when this bug appears. Also when the bug appears, I can make a normal internet wifi connection with the manual system tools of archlinux (for example wifi-menu), If I disable NetworkManager. Anyway dhclient in my system has no config in /etc so it uses default options.
That looks like a problem in NetworkManager itself or in the dhcp client. We, from KDE, do not develop either of them, so you should contact NetworkManager developers [1] [2] about this problem. Probably they can debug the problem and figure out what is going on. [1] https://mail.gnome.org/mailman/listinfo/networkmanager-list [2] https://bugzilla.gnome.org/buglist.cgi?quicksearch=networkmanager
You can also try setting IPv6 to local-link: https://bbs.archlinux.org/viewtopic.php?id=146261