Arch Linux

shadowtech

Member

Registered: 2010-08-06

Posts: 4

No internet connectivity after router reboot on LAN

Hi, first time post here. I've been using Arch for the last couple months and loving it, but I've recently noticed a strange networking issue. My machine is completely up to date using pacman.

My Issue
After rebooting my D-Link DIR 655 router, the Arch box (2.6.34-ARCH) isn't able to connect to the outside world. I can still connect to the box through the local LAN, and even remotely through SSH (over the internet). I can still ping my default gateway as well. The problem seems to be with the Arch box getting its own connection to outside networks.

If I ping after a reboot, I will get this:

$ ping google.com
ping: unknown host google.com

If I issue a pacman -Syy, I will get this:

$ sudo pacman -Syy
:: Synchronizing package databases...
error: failed retrieving file 'core.db.tar.gz' from mirror.csclub.uwaterloo.ca : Transient resolver failure

I can fix this manually by restarting the network daemon:

 $ /etc/rc.d/network restart

Networking section of my rc.conf

# -----------------------------------------------------------------------
# NETWORKING
# -----------------------------------------------------------------------
#
# HOSTNAME: Hostname of machine. Should also be put in /etc/hosts
#
HOSTNAME="Servo"

# Use 'ifconfig -a' or 'ls /sys/class/net/' to see all available interfaces.
#
# Interfaces to start at boot-up (in this order)
# Declare each interface then list in INTERFACES
#   - prefix an entry in INTERFACES with a ! to disable it
#   - no hyphens in your interface names - Bash doesn't like it
#
# DHCP:     Set your interface to "dhcp" (eth0="dhcp")
# Wireless: See network profiles below
#

#Static IP example
#eth0="eth0 192.168.0.2 netmask 255.255.255.0 broadcast 192.168.0.255"
eth0="dhcp"
INTERFACES=(eth0)

# Routes to start at boot-up (in this order)
# Declare each route then list in ROUTES
#   - prefix an entry in ROUTES with a ! to disable it
#
gateway="default gw 192.168.0.1"
ROUTES=(!gateway)

# Enable these network profiles at boot-up.  These are only useful
# if you happen to need multiple network configurations (ie, laptop users)
#   - set to 'menu' to present a menu during boot-up (dialog package required)
#   - prefix an entry with a ! to disable it
#
# Network profiles are found in /etc/network.d
#
# This now requires the netcfg package
#
#NETWORKS=(main)

My Question
Is it possible to get the network daemon to automatically regrab the proper networking information so I don't have to manually restart the daemon after a router reboot or network outage?

karol

Archivist

Registered: 2009-05-06

Posts: 25,440

Re: No internet connectivity after router reboot on LAN

There was a similar thread a couple days ago.
You can try 'if you can't ping google, restart network / dhcpcd'.

ralvez

Member

From: Canada

Registered: 2005-12-06

Posts: 1,718

Website

Re: No internet connectivity after router reboot on LAN

It looks like you do not have dhcp update your /etc/resolv.conf
A solution (while you troubleshoot the problem) would be to edit your /etc/resolv.conf and add
nameserver xxx.xxx.xxx.xxx
where xxx is the address of your router.

Assuming you do get and IP address in your arch box that should solve your problem for now.

R.

shadowtech

Member

Registered: 2010-08-06

Posts: 4

Re: No internet connectivity after router reboot on LAN

Thanks for the help. I solved the problem, somewhat.

What was happening, was after a router reboot (network outage) the resolv.conf file was not being updated with the correct nameserver data.
I used the "Preserve DNS settings" instructions (https://wiki.archlinux.org/index.php/Resolv.conf) to prevent the daemon from overwriting this file with a blank file.

I'm not sure why Arch can't pull down DNS data from my router after network loss, but this seems to fix the problem for now, as my DNS servers (well, google's loaded into my DIR 655 router) never change.