DNS, DHCP problems after fresh LMDE install

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DNS, DHCP problems after fresh LMDE install

Postby TomRoche on Wed Apr 16, 2014 8:43 pm

summary: On a laptop with a nearly-new install of LMDE-201403, I had a DNS problem (fixed) and still have a DHCP problem (not fixed).

details:

Recently I installed LMDE-201403/UP8 on an older ThinkPad, which I have been using successfully on my home network. Yesterday I took it to a friend's house, where I was able to connect wirelessly and by wire to her routers, but was completely unable to DNS. I fixed the DNS problem after reading this

When resolvconf is properly installed, the resolv.conf configuration file at /etc/resolv.conf is replaced by a symbolic link to /etc/resolvconf/run/resolv.conf and the resolver instead uses the configuration file that is dynamically generated by resolvconf at /etc/resolvconf/run/resolv.conf.


so I did

Code: Select all
$ which resolvconf
[1]$ sudo which resolvconf
> /sbin/resolvconf

$ ls -al /etc/resolv.conf
> -rw-r--r-- 1 root tlroche 174 Apr 11 13:48 /etc/resolv.conf
$ cat /etc/resolv.conf
> # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
> #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
> nameserver 192.168.1.1

$ ls -al /etc/resolvconf/run/
> -rw-r--r--  1 root root   0 Apr 15 17:34 enable-updates
> drwxr-xr-x  2 root root  60 Apr 15 17:34 interface
> -rw-r--r--  1 root root 192 Apr 15 17:34 resolv.conf

$ cat /etc/resolvconf/run/resolv.conf
> # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
> #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
> nameserver 192.168.15.1
> search local.tld

$ sudo ln -sf ./resolvconf/run/resolv.conf ./resolv.conf
$ popd
$ ls -al /etc/resolv.conf
> lrwxrwxrwx 1 root root 28 Apr 15 17:53 /etc/resolv.conf -> ./resolvconf/run/resolv.conf
$ nslookup www.google.com
# success!


and have since then been able to DNS normally ... until I release/renew DHCP:

While debugging the DNS problem, I found that the laptop in question is unable to get an IP number (v4, anyway) after release/renew-ing a DHCP lease, even after the above fix. If I boot the box while connected wirelessly (note I get similar results if connected by wire to the router), I see

Code: Select all
$ sudo ifconfig -a
> eth0      Link encap:Ethernet  HWaddr [...]
...
> lo        Link encap:Local Loopback
...
> wlan0     Link encap:Ethernet  HWaddr [...]
>           inet addr:192.168.15.71  Bcast:192.168.15.255  Mask:255.255.255.0
>           inet6 addr: [...]/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:4037 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:4351 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:1242931 (1.1 MiB)  TX bytes:803482 (784.6 KiB)


(I also get an IP# if I boot while connected by wire.) However, if I then release/renew, I lose IP (note error regarding "broadcast interfaces") until I restart:

Code: Select all
tlroche@tlrW510 ~ $ sudo dhclient -r ; sudo dhclient -v ; sudo ifconfig -a
> Reloading /etc/samba/smb.conf: smbd.
> Internet Systems Consortium DHCP Client 4.2.4
> Copyright 2004-2012 Internet Systems Consortium.
> All rights reserved.
> For info, please visit https://www.isc.org/software/dhcp/

> No broadcast interfaces found - exiting.
> eth0      Link encap:Ethernet  HWaddr [...]
...
> lo        Link encap:Local Loopback
...
> wlan0     Link encap:Ethernet  HWaddr [...]
>           inet6 addr: [...]/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:4101 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:4417 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:1252378 (1.1 MiB)  TX bytes:818546 (799.3 KiB)


Am I doing this (DHCP re-leasing) incorrectly? If so, how to do? If not, how to fix?
TomRoche
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