Automatic dhcpcd with eth0 ?

icmp_request · Posted: Sun Aug 22, 2010 4:27 pm Post subject: Automatic dhcpcd with eth0 ?

Hello! Is there a way that, as happens in some other distos, as soon as I plug a cable to my eth0 interface the system recognizes it and starts dhcpcd?

So I don't have to manually re-run /etc/init.d/net.eth0 restart ...

Thanks!
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Jimini · l33t Joined: 31 Oct 2006 Posts: 605 Location: Germany

ifplugd could be the thing you are looking for.

Best regards,
Jimini
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icmp_request · Posted: Sun Aug 22, 2010 4:36 pm Post subject:

I'll take a look...

Thanks so much Jimini! =)
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hedmo · Veteran Joined: 29 Aug 2009 Posts: 1334 Location: sweden

nano -w /etc/conf.d/net

set

config_eth0=( "dhcp" )

save and quit and type

rc-update add net.eth0 default

UberLord · Posted: Mon Aug 23, 2010 8:36 am Post subject:

depontius · Advocate Joined: 05 May 2004 Posts: 3526

UberLord · Posted: Mon Aug 23, 2010 1:56 pm Post subject:

depontius · Advocate Joined: 05 May 2004 Posts: 3526

I don't use zeroconf. I don't use wired and wireless at the same time. Still, getting rid of ifplugd will be a step forward for me. I have my own net adaptation scripts, and ifplugd seems to interfere with them a bit. Simpler is frequently better. Thanks.
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icmp_request · Posted: Mon Aug 23, 2010 2:33 pm Post subject:

Amity88 · Posted: Tue Aug 24, 2010 10:52 am Post subject:

dhcp seems to autoconfigure eth0 when I plug in the cable.... BUT it waits for a carrier at startup, wasting time if I haven't plugged the cable. I use netplug to solve this. Is there an alternative?
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UberLord · Posted: Tue Aug 24, 2010 10:54 am Post subject:

Amity88 · Posted: Tue Aug 24, 2010 11:00 am Post subject:

I use dhcpcd. The carrier detection timout was the problem, I use WiFi most of the time, so every time I turn on my computer I had to wait while dhcpcd figures out that there's no cable in the ethernet port. Netplug solves this.
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UberLord · Posted: Tue Aug 24, 2010 11:29 am Post subject:

Amity88 · Posted: Tue Aug 24, 2010 12:33 pm Post subject:

I have kernel 2.6.34 and dhcpcd 4.0.15. I'll check out your manual and experiment with it, and let you know what happens

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Amity88 · Posted: Tue Aug 24, 2010 1:19 pm Post subject:

mmmkkay,
The result of the experiment.

first I uninstalled netplug. Then when I boot up my computer it says

UberLord · Posted: Tue Aug 24, 2010 1:31 pm Post subject:

Amity88 · Posted: Tue Aug 24, 2010 1:34 pm Post subject:

Thanks for the info.
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depontius · Advocate Joined: 05 May 2004 Posts: 3526

I have some automation I've written, which I hook into dhcpcd. In the past I used the "dhcpcd-eth0.exe" hook to run it, but I'm now trying to use the run-hooks support. I've added my own script, "60-netAdapt" which should run after all of the other run-hook scripts. In that script, I figure out what network I'm on and reconfigure, start, and stop services based on that network. For instance, if I'm at work I start openafs-client, if I'm at home I do an nfs mount, if I'm elsewhere I make sure gdm is started listening on unix sockets only, no tcp, etc.

My problem appears to be that the net really isn't up when "60-netAdapt" is being run. My attempts to start services fail with some sort of "eth0 is not up" message. This machine is still running ifplugd, which based on conversations here I plan to remove when I get time, and maybe that's my problem. Or am I supposed to hook in some different way, to know that the net is truly all the way up when I run my stuff?
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icmp_request · Posted: Wed Aug 25, 2010 2:02 pm Post subject:

Guys the solution I've found is MUCH simpler!

First:

# rc-update del net.eth0 default

But this doesn't prevent net.eth0 from running because it's linked to net.lo, so:

# rm /etc/init.d/net.eth0

Now add the following line to /etc/conf.d/local.start:

/sbin/dhcpcd -C resolv.conf -b eth0

- In this case, I've passed the -C option because I wish to preserve my resolv.conf, if you do not:

/sbin/dhcpcd -b eth0

Done! I don't suffer from boot timeouts anymore, and when I plug a cable, it's automatically configured.

Should work unless you need to have a network partition/volume mounted at boot time.

Edit: Usually when I update my whole system, the link net.eth0 is restored on /etc/init.d... I've tried to do a simple: " # touch /etc/init.d/net.eth0 " after removing it. I don't know if it works, haven't tested, but at least should.

Edit2: If having any issues about eth0 not being up, try to add before the dhcpcd line: #ifconfig eth0 up
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UberLord · Posted: Wed Aug 25, 2010 2:09 pm Post subject:

depontius · Advocate Joined: 05 May 2004 Posts: 3526

I'm looking at this morning's logs, and see that netAdapt was first called at 5:28:01 with reason=BOUND. Following that my services failed to start because eth0 was not up. Some of my services, such as dnsmasq, were in the default runlevel and I was just restarting them in order to tweak the configuration. For each service I restart rather than start, because it may (like dnsmasq) have already been started. For each service I get one message from ifplugd followed by one message from rc-scripts that the service has not yet been started. Following all of these messages, I got a message from ifplugd that mount.mfs4 failed because of a temporary failure in name resolution. After that, I got messages from ifplugd and dnsmasq that it was starting. (Talk about timing errors.) By 5:28:13 sshd had been started by ifplugd, and I believe that was the last of the actions triggered by netAdapt. I guess the big issue here is that my nfs mount tried to happen prior to dnsmasq.

I suspect a large part of my problem here is ifplugd, but I suspect not all. As I said, netAdapt was first called at 5:28:01 with reason=BOUND, at which time I would expect the network to be up. At 5:28:02 I start getting messages from ifplugd telling me that it will start things when eth0 is started. I continue getting defer messages until at 5:28:04 I see ifplugd starting dnsmasq. (Actually it first tried and failed to do mount.nfs4 just before that.) Maybe my problem still is ifplugd, in that it has deferred service startup and isn't necessarily starting things in the right order. Maybe it's Johnny-come-lately to the news that eth0 is up, and still thinks it needs to be deferring.
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mamac · l33t Joined: 29 Feb 2004 Posts: 890

UberLord · Posted: Sat Dec 04, 2010 9:28 pm Post subject:

mamac · l33t Joined: 29 Feb 2004 Posts: 890

I was only searching how dhcpcd-5 would start, one just need to remove dhcpcd options from /etc/conf.d/net, this is valid with baselayout-1, gentoo-sources-2.6.35-r12 and dhcpcd-5 (dhcpcd-4 will start regardless if the option is set or not).
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