[Discuss] networking problem

[Jerry Feldman]

On 11/22/2011 11:23 AM, j. daniel moylan wrote:
> i've recently installed ubuntu 10.10 on my asus eee pc 1005ha.  it gave me
> warning messages on bootup:
>
>   waiting for network configuration
>   waiting  up to 60 more sec for network configuration
>   booting system without full network configuration
>
> sure enough, the builtin wireless n didn;t come up.  i tried the
> networkmanager icon, and that came up with the first four lines light
> grey.  perservering, i punched the bottom line "edit connections", did
> that, and saved it but no network came up. i tried /etc/init.d/networking
> restart and that indeed brought up the network 192.168.0.103 as shown by
> ifconfig.  however that issued a warning that the command was deprecated
> and that everything might not come up (but no mention of the favored
> command).  none the less, things seemed to work fine -- the browser
> connected as desired, mutt worked and i was happy though i needed to do the
> init.d thing each time i booted.
>
> today, i was able to bring up 192.168.0.103, but only locally. i can ping
> 192.168.0.1 but can't seem to get out past the local net.  firefox doesn't
> connect out and email doesn't work.
I found a few quirks with Ubuntu on wireless Networking.
First, on the first boot after installation, sometimes the wireless
firmware is not loaded. This depends on the wireless chips. When I
bought my eeePC under Windows the wireless was very flaky so I returned
the system and eventually bought an Acer Aspire One. The wireless on it
generally comes up ok. Recently I upgraded to Fedora 16 and it failed to
come up, and when I checked the WPA password, I found that one character
was wrong.
There are several things that one should do before asking for help:
Check to make sure the wireless is connecting. Network manager should
tell you what it is doing, such as "connecting", obtaining IP address, ..."
Once connected, ifconfig should show an IP address.
The next thing is to determine the routing table, as I mentioned before
the 'route' or 'netstat -nr' should tell you the route status. The most
important thing is the default route. This should be set up
automatically by network manager. If you can ping an outside IP address
then the network is ok. Sometimes getting the IP address of your ISP's
router is useful. Your router has this info. 
The last thing is the DNS servers. /etc/resolv.conf is where the
information is kept temporarily. Network manager will overwrite this.
Make sure the nameservers are active. To check a nameserver, I use dig:
dig @<nameserver IP address> <name to resolv>
A bad nameserver will cause anything that uses names to fail.

If you go through those steps and post the routing table and the
resolv.conf, it will be easier to diagnose your problem.


-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
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