View Full Version : [ubuntu] Need to disable IPv6 in 9.10

January 8th, 2010, 06:54 AM
Hi there. I just switched to Karmic from 7.10 (Fiesty). I tackled the grub2's problems with booting from an ext4 partition with gusto, and got this slick new version up and running. I was suprised to see that this version recognizes my Belkin USB wireless n device "out of the box" which is something previous versions have never done. I was thinking the toughest of my problems was behind me, however the network dialog recognizes every wireless LAN in a 3 block radius (at least that much) with the exception of my own. I played with all my router settings and eventually disabled all security, essentially draping my neighborhood in wifi. My network still went unrecognized and yes, my SSID is broadcasted. I had my suspicions of the problem based on networking issues I've had with previous versions of ubuntu. Namely, that IPv6 is enabled from the word go in ubuntu, which for the now, only seems to cause issues. In previous releases you could edit /etc/modprobe.d/aliases to disable the IPv6, however in 9.10 this file is conspicuously absent. Does anyone know how to disable IPv6 in this release?

Here's some additional information:

My router worked with 7.10 and is configured for a WPA + WPA2 PSK security setup, using TKIP encrytion and a WPA key. It functions just fine. I would prefer to have it set up with a WPA + WPA2 key with TKIP + AES encryption as well as some other heightened security, but then my Wii/Blackberry/other non-desktop devices don't support this. *shrug* :D Another interesting bug to mention is in 7.10 my wireless connection would only stay connected for some irregular interval before my network settings were overwritten with some crazy long WPA passkey. Is there an fstab-like file I can edit to prevent this if the same problem arises in this version? All other settings remained intact but the passkey, and reentering that or unplugging/replugging the usb device and reentering the key always solved the problem, until the next interval anyway.

jukebox-zero@jukebox-zero-desktop:~$ lsusb
Bus 001 Device 003: ID 03f0:3307 Hewlett-Packard
Bus 001 Device 002: ID 050d:815c Belkin Components
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 002: ID 0566:3107 Monterey International Corp.
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

jukebox-zero@jukebox-zero-desktop:~$ lsmod
Module Size Used by
ndiswrapper 185404 0
ipt_MASQUERADE 2204 1
xt_state 1820 1
ipt_REJECT 2812 2
xt_tcpudp 2780 4
nf_nat_h323 6204 0
nf_conntrack_h323 48904 1 nf_nat_h323
nf_nat_pptp 2844 0
nf_conntrack_pptp 5984 1 nf_nat_pptp
nf_conntrack_proto_gre 5344 1 nf_conntrack_pptp
nf_nat_proto_gre 2080 1 nf_nat_pptp
nf_nat_tftp 1340 0
nf_conntrack_tftp 4048 1 nf_nat_tftp
nf_nat_sip 6300 0
nf_conntrack_sip 17872 1 nf_nat_sip
nf_nat_irc 2012 0
nf_conntrack_irc 4992 1 nf_nat_irc
nf_nat_ftp 2652 0
nf_conntrack_ftp 6880 1 nf_nat_ftp
iptable_nat 5500 1
nf_nat 17808 9 ipt_MASQUERADE,nf_nat_h323,nf_nat_pptp,nf_nat_prot o_gre,nf_nat_tftp,nf_nat_sip,nf_nat_irc,nf_nat_ftp ,iptable_nat
nf_conntrack_ipv4 13352 4 iptable_nat,nf_nat
nf_conntrack 67608 18 ipt_MASQUERADE,xt_state,nf_nat_h323,nf_conntrack_h 323,nf_nat_pptp,nf_conntrack_pptp,nf_conntrack_pro to_gre,nf_nat_tftp,nf_conntrack_tftp,nf_nat_sip,nf _conntrack_sip,nf_nat_irc,nf_conntrack_irc,nf_nat_ ftp,nf_conntrack_ftp,iptable_nat,nf_nat,nf_conntra ck_ipv4
nf_defrag_ipv4 1756 1 nf_conntrack_ipv4
nls_iso8859_1 3740 1
nls_cp437 5372 1
isofs 31620 1
vfat 10716 1
fat 51452 1 vfat
udf 80900 0
crc_itu_t 1852 1 udf
cbc 3516 125
aes_i586 8124 126
aes_generic 27484 1 aes_i586
binfmt_misc 8356 1
snd_intel8x0 30168 2
snd_ac97_codec 101216 1 snd_intel8x0
ac97_bus 1532 1 snd_ac97_codec
snd_pcm_oss 37920 0
snd_mixer_oss 16028 1 snd_pcm_oss
snd_pcm 75296 3 snd_intel8x0,snd_ac97_codec,snd_pcm_oss
snd_seq_dummy 2656 0
snd_seq_oss 28576 0
snd_seq_midi 6432 0
rt2870sta 488820 0
arc4 1660 2
iptable_filter 3100 1
snd_rawmidi 22208 1 snd_seq_midi
ecb 2524 3
ip_tables 11692 2 iptable_nat,iptable_filter
dm_crypt 12928 0
snd_seq_midi_event 6940 2 snd_seq_oss,snd_seq_midi
x_tables 16544 6 ipt_MASQUERADE,xt_state,ipt_REJECT,xt_tcpudp,iptab le_nat,ip_tables
rt2800usb 37372 0
snd_seq 50224 6 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_seq_mid i_event
rt2x00usb 11548 1 rt2800usb
snd_timer 22276 2 snd_pcm,snd_seq
snd_seq_device 6920 5 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_rawmidi ,snd_seq
rt2x00lib 29756 2 rt2800usb,rt2x00usb
led_class 4096 1 rt2x00lib
ppdev 6688 0
snd 59204 14 snd_intel8x0,snd_ac97_codec,snd_pcm_oss,snd_mixer_ oss,snd_pcm,snd_seq_oss,snd_rawmidi,snd_seq,snd_ti mer,snd_seq_device
input_polldev 3716 1 rt2x00lib
joydev 10272 0
parport_pc 31940 1
dell_wmi 2564 0
shpchp 32272 0
dcdbas 7292 0
soundcore 7264 1 snd
snd_page_alloc 9156 2 snd_intel8x0,snd_pcm
mac80211 181236 2 rt2x00usb,rt2x00lib
cfg80211 93052 2 rt2x00lib,mac80211
crc_ccitt 1852 1 rt2800usb
psmouse 56180 0
serio_raw 5280 0
lp 8964 0
parport 35340 3 ppdev,parport_pc,lp
usbhid 38208 0
usb_storage 52544 1
e1000 119264 0
tulip 48320 0
intel_agp 27484 1
agpgart 34988 1 intel_agp
floppy 54916 0

jukebox-zero@jukebox-zero-desktop:~$ dmesg | tail
[20037.107626] wlan1: associate with AP 00:11:50:5f:74:9f
[20037.109775] wlan1: RX AssocResp from 00:11:50:5f:74:9f (capab=0x401 status=0 aid=3)
[20037.109784] wlan1: associated
[20037.118346] wlan1: disassociating by local choice (reason=3)
[20091.989913] wlan1: Trigger new scan to find an IBSS to join
[20095.000283] wlan1: Trigger new scan to find an IBSS to join
[20098.000034] wlan1: Trigger new scan to find an IBSS to join
[20101.000380] wlan1: Trigger new scan to find an IBSS to join
[20101.812853] wlan1: Creating new IBSS network, BSSID de:c5:ed:73:5a:ba
[20102.104020] wlan1: no IPv6 routers present
jukebox-zero@jukebox-zero-desktop:~$Notice that last line printed by dmesg | tail ?

It's interesting to note this is a Belkin USB Wireless n device, which seems to work fine with no restricted drivers installed although when I installed the rt2080 driver that came with using ndisgtk I am served a dialog that it cannot confirm the device is detected, or something along those lines, though in windows wireless drivers dialog it literally says "Hardware detected: Yes." None the less, as it can see several other wireless networks, and can even connect to some (fastest pirated speed got ndisgtk apt-get installed at 30kbp/s) and only fails to see my own, I suspect IPv6 is at fault. Or at the least, disabling it is the next logical step. I've located one solution though I would rather not alter my grub any further if I can avoid this.

Edit /etc/default/grub file
gksudo gedit /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT=”ipv6.disable=1 quiet splash”
Save and exit the file
If there's an alternative to this I'd be interested, I'd like to leave the grub as intact as possible until I get this install fully up and running so I know which problems I caused and what broke what. I already changed the grub once for the aformentioned booting from ext4 partition glich.

Can anyone help me tackle this issue so I can move on to my next problem? ;)

- A. Venez

Brandon Williams
January 9th, 2010, 07:47 PM
I would be surprised if IPv6 is really thr problem here. It seems that IPv6 wouldn't come into play until you were already associated with the access point, and it sound like you aren't even getting that far. Still, it's always possible that there's some relationship that isn't obvious, so ...

You can disable IPv6 with sysctl:

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1

If that solves the problem, then you can make it persistent by adding the following line to /etc/sysctl.conf:

net.ipv6.conf.all.disable_ipv6 = 1