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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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 Posted: Tue May 22, 2007 8:34 pm Post subject: [SOLVED]How to let DHCP override my /etc/resolv.conf file |
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Hi!
I switch networks constantly, but I don't understand why I can't automatically obtain DNS information via DHCP.
My /etc/conf.d/net file contains:
| Code: |
config_eth0=( "dhcp" )
modules=( "iwconfig" )
dhcp_eth0="nontp nonis nodns"
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But it doesn't work. A comment in this file says: "This blank configuration will automatically use DHCP for any net.*", but commenting everything doesn't help either.
What can I do?
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Last edited by germanobax on Fri May 25, 2007 1:58 pm; edited 1 time in total |
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jmbsvicetto
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Joined: 27 Apr 2005
Posts: 4735
Location: Angra do Heroísmo (PT)
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| Posted: Tue May 22, 2007 8:38 pm Post subject: Re: How to let DHCP override my /etc/resolv.conf file |
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Hi.
| germanobax wrote: | Hi!
I switch networks constantly, but I don't understand why I can't automatically obtain DNS information via DHCP. |
You might want to try ethtool and resolvconf-gentoo.
| germanobax wrote: |
My /etc/conf.d/net file contains:
| Code: |
config_eth0=( "dhcp" )
modules=( "iwconfig" )
dhcp_eth0="nontp nonis nodns"
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You really don't want nodns in there or it won't use the dns settings from the DHCP server.
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Jorge.
Your twisted, but hopefully friendly daemon.
AMD64 / x86 / Sparc Gentoo
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Tue May 22, 2007 9:02 pm Post subject: |
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Thanks for your reply, but I don't know why I should use ethtool, neither how to use it to solve this problem. resolvconf-gentoo didn't help me too.
I removed the "nodns" part from the /etc/conf.d/net file, but no go.
The "great" solution I found is to boot with the LiveCD and copy the /etc/resolv.conf of the livecd to my disk everytime I switch networks. That's very annoying.
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mudrii
l33t
Joined: 26 Jun 2003
Posts: 789
Location: Singapore
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| Posted: Wed May 23, 2007 4:34 am Post subject: |
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try to use the command
dhcpcd eth0
or
dhcpcd -HD eth0
to refresh IP settings in new network
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toralf
Developer
Joined: 01 Feb 2004
Posts: 3942
Location: Hamburg
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| Posted: Wed May 23, 2007 7:28 am Post subject: |
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| Have a look into /etc/conf.d/domainname for the var OVERRIDE. |
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Wed May 23, 2007 12:50 pm Post subject: |
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Thanks for your help, guys. Unfortunately, things aren't working out yet. Let's see...
| mudrii wrote: | try to use the command
dhcpcd eth0 |
Didn't work.
| mudrii wrote: |
dhcpcd -HD eth0
to refresh IP settings in new network
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Says that "D" is an invalid option. I tried with just "H", but that didn't work too.
| toralf wrote: | | Have a look into /etc/conf.d/domainname for the var OVERRIDE. |
Here's the output:
| Code: |
jbackes-laptop jbackes # cat /etc/conf.d/domainname
OVERRIDE=1
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... still using a LiveCD... 
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toralf
Developer
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Posts: 3942
Location: Hamburg
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| Posted: Wed May 23, 2007 12:55 pm Post subject: |
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Ehm, what about changing the line | Code: | | dhcp_eth0="nontp nonis nodns" |
into at least |
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Wed May 23, 2007 1:20 pm Post subject: |
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| toralf wrote: | Ehm, what about changing the line | Code: | | dhcp_eth0="nontp nonis nodns" |
into at least |
Did that:
| Code: |
cat /etc/conf.d/net
config_eth0=( "dhcp" )
modules=( "iwconfig" )
dhcp_eth0="nontp"
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But the problem persists.
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Suicidal
l33t
Joined: 30 Jul 2003
Posts: 959
Location: /dev/null
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| Posted: Wed May 23, 2007 3:15 pm Post subject: |
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I switch between my external lan which has dhcp and my (disjointed) local lan that does not have dhcp I have the following set:
| Code: | modules=( "iproute2" )
config_eth0=( "dhcp" )
dhcp_eth0="release nontp"
dns_domain_eth0="myinternaldomain.local"
dns_servers_eth0="10.200.0.35 10.200.0.28 "
dns_search_eth0="myinternaldomain.local"
dns_options_eth0=( "timeout 1" "rotate" )
ntp_servers_eth0=( "10.200.0.18" "pool.ntp.org" )
fallback_eth0=( "10.200.78.221 netmask 255.255.255.0 broadcast 10.200.78.255" )
fallback_route_eth0=( "default via 10.200.78.1" ) |
eth0 will default to dhcp which will set the following in my /etc/recolv.conf
| Code: | search myexternaldomain.com
nameserver 192.168.1.1
nameserver 192.168.1.1 |
If dhcp is not recieved networking will fallback to my fallback_eth0 ip and gateway, and it will set my dns_* entries
I think that:
is your problem
If you switch between alot of subnets you might want to look at the # ARPING Gateway configuration section in /etc/conf.d/net.example |
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Wed May 23, 2007 3:43 pm Post subject: |
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The problem is that most of the time I don't know or can't discover the correct IP, mask, domain, etc by myself (except when using the liveCD). DHCP should do the work of discovering all this information for me.
Mostly I simply don't know to which network I'm switching to, I just switch. DHCP gets an IP adress, but it doesn't set the DNS information in /etc/resolv.conf.
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germanobax
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Joined: 28 Apr 2005
Posts: 96
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| Posted: Thu May 24, 2007 3:37 pm Post subject: |
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Does anybody have another suggestion?
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toralf
Developer
Joined: 01 Feb 2004
Posts: 3942
Location: Hamburg
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| Posted: Thu May 24, 2007 3:45 pm Post subject: |
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| To sum it up, you use net-misc/dhcpcd-3.0.16-r1 or something similar and made an "/etc/init.d/net.eth0 restart" or something similar (eg during boot "start" is used), have a (nearly) stable Gentoo system without any obscure USE flags and it does not work for you, right ? (BTW, nice avatar) |
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Thu May 24, 2007 4:04 pm Post subject: |
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Exactly
| Code: |
jbackes@jbackes-laptop ~ $ esearch dhcpcd
[ Results for search key : dhcpcd ]
[ Applications found : 1 ]
* net-misc/dhcpcd
Latest version available: 3.0.16-r1
Latest version installed: 3.0.16-r1
... |
I always use "/etc/init.d/net.eth0 restart". My make.conf contains:
| Code: |
jbackes@jbackes-laptop ~ $ cat /etc/make.conf
CFLAGS="-O3 -pipe -march=athlon64"
CHOST="x86_64-pc-linux-gnu"
CXXFLAGS="${CFLAGS}"
MAKEOPTS="-j2"
GENTOO_MIRRORS="http://adelie.polymtl.ca/ http://gentoo.osuosl.org/ ftp://distro.ibiblio.org/pub/linux/distributions/gentoo/ http://distro.ibiblio.org/pub/linux/distributions/gentoo/ http://www.las.ic.unicamp.br/pub/gentoo/ ftp://ftp.las.ic.unicamp.br/pub/gentoo/ http://gentoo.inode.at/ "
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
FEATURES="parallel-fetch userfetch ccache"
CCACHE_SIZE="2G"
CCACHE_DIR="/var/tmp/ccache"
LINGUAS="pt_BR pt"
VIDEO_CARDS="radeon fglrx vmware"
INPUT_DEVICES="keyboard joystick mouse synaptics vmmouse"
USE = "3dnow a52 aac aalib aiglx apache2 apm bash-completion bindist bzip2
cddb cdparanoia css daap dga directfb dts dv dvb exif fbcon ffmpeg flac
ftp ggi gnutls gphoto2 graphviz idn imagemagick ipod jack java
javascript jbig jikes joystick jpeg2k junit lcms libcaca libnotify
libsamplerate lm_sensors lua matroska mmap mng mono mplayer musepack
musicbrainz nas nocd nsplugin odbc openal php postgres samba scanner
sndfile speex symlink tetex theora threads type1 usb v4l vcd videos
visualization wifi wmf wxwindows x264 xine xinerama xosd xscreensaver
xvid"
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And my /etc/portage/package.use has:
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jbackes@jbackes-laptop ~ $ cat /etc/portage/package.use
dev-java/sun-jdk doc
kde-base/kopete addbookmarks alias autoreplace connectionstatus contactnotes gadu groupwise highlight history irc jingle latex netmeeting nowlistening sametime slp sms statistics texteffect translator webpresence winpopup yahoo
app-misc/beagle chm doc galago ole
sys-apps/lm_sensors sensord
x11-libs/qt qt3support
gnome-base/nautilus beagle
sys-power/cpufreqd pmu
games-rpg/nwn-data hou nowin sou
games-rpg/nwn hou sou
games-rpg/nwn-cep hou sou
mail-client/mozilla-thunderbird replytolist
net-www/mplayerplug-in divx gmedia realmedia wmp
media-video/mplayer 3dnowext amr bl cpudetection dv dvdnav enca lirc live lzo mmxext mp2 pnm rar real rtc srt tga tivo v4l2 xanim xvmc
www-servers/tomcat admin doc examples java5
media-video/vlc cdda dc1394 httpd live mod rtsp sdl-image shout skins stream vlm
media-video/transcode mjpeg extrafilters fame lzo network v4l2
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Is there a problem in some use flags, that I'm not aware of?
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UberLord
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Joined: 18 Sep 2003
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Thu May 24, 2007 4:16 pm Post subject: |
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YES!
| Code: |
jbackes-laptop jbackes # cat /var/lib/dhcpcd/dhcpcd-eth0.info
IPADDR='143.54.10.149'
NETMASK='255.255.255.0'
BROADCAST='143.54.10.255'
ROUTES='0.0.0.0,0.0.0.0,143.54.10.1'
DNSDOMAIN='inf.ufrgs.br'
DNSSERVERS='143.54.11.9 143.54.11.7 143.54.9.1'
DHCPSID='143.54.11.9'
DHCPSNAME=''
LEASETIME='3600'
RENEWALTIME='1800'
REBINDTIME='3150'
INTERFACE='eth0'
CLASSID='dhcpcd 3.0.16'
CLIENTID='00:0f:b0:74:09:41'
DHCPCHADDR='00:0f:b0:74:09:41'
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At least the LiveCD can be discarded now... But /etc/resolv.conf still needs manual editing.
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toralf
Developer
Joined: 01 Feb 2004
Posts: 3942
Location: Hamburg
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| Posted: Thu May 24, 2007 4:27 pm Post subject: |
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No, you haven't any obscure compiler flags, look at my settings : | Code: | # These settings were set by the catalyst build script that automatically built this stage
# Please consult /etc/make.conf.example for a more detailed example
CFLAGS="-O2 -march=pentium-m -fomit-frame-pointer -pipe"
CHOST="i686-pc-linux-gnu"
CXXFLAGS="${CFLAGS}" |
Ok, except that -O3 had have some rare bugs in the past compared to -O2 but I won't believe that this is the case here. ANd I hope that the file permissions are ok : | Code: | tfoerste@n22 ~ $ ls -l /etc/resolv.conf
-rw-r--r-- 1 root root 71 May 24 17:35 /etc/resolv.conf
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? |
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Thu May 24, 2007 4:31 pm Post subject: |
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Yes, they are (but I don't know what that 88 means):
| Code: |
jbackes@jbackes-laptop ~ $ ls -l /etc/resolv.conf
-rw-r--r-- 1 root root 88 2007-05-23 10:18 /etc/resolv.conf
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jmbsvicetto
Moderator
Joined: 27 Apr 2005
Posts: 4735
Location: Angra do Heroísmo (PT)
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| Posted: Thu May 24, 2007 4:42 pm Post subject: |
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| germanobax wrote: | Yes, they are (but I don't know what that 88 means):
| Code: |
jbackes@jbackes-laptop ~ $ ls -l /etc/resolv.conf
-rw-r--r-- 1 root root 88 2007-05-23 10:18 /etc/resolv.conf
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That is the size of the file.
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Jorge.
Your twisted, but hopefully friendly daemon.
AMD64 / x86 / Sparc Gentoo
Help answer || emwrap.sh
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UberLord
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Thu May 24, 2007 4:54 pm Post subject: |
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That's crazy:
| Code: |
jbackes-laptop jbackes # dhcpcd -n eth0
jbackes-laptop jbackes # cat /etc/resolv.conf
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Gives nothing.
BUT resolvconf -l gives the correct information:
| Code: |
jbackes-laptop jbackes # resolvconf -l
# resolv.conf for interface eth0
# Generated by dhcpcd for interface eth0
search inf.ufrgs.br
nameserver 143.54.11.9
nameserver 143.54.11.7
nameserver 143.54.9.1
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Man, /etc/resolv.conf is EMPTY... It should look like the output of resolvconf -l
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UberLord
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germanobax
Tux's lil' helper
Joined: 28 Apr 2005
Posts: 96
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| Posted: Fri May 25, 2007 1:58 pm Post subject: |
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| UberLord wrote: | I'm betting you didn't do "emerge --config resolvconf-gentoo" did you?
EDIT: Infact from a previous post I can see you didn't. resolvconf only works when /etc/resolv.conf is a symlink to the resolvconf one. |
You're right! I did that, and it finally works!
Thank you.
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