[plug] Wireless Internet

[Craig Ringer]

On Tue, 2005-06-14 at 17:36 +0800, Chris Watt wrote:
> Hi Guys,
> 
> Just finished setting up Dianne's computer today at Midway and we have
> a small problem.  While it connects to the wireless network no
> trouble, she can't get into the internet at all.  Het email times ot
> and not even google comes up.  Any ideas what could be causing this? 

It'd only be guesswork. Instead, let me provide a series of basic
network troubleshooting hints / steps to collect the information
required to properly diagnose the problem.

Is this a Linux box? WinXP?  I'm assuming Linux, so:

First you need to check that the network interface has the right IP
address. You can use `ifconfig' for that. Please post the output of all
these commands if you follow up with any additional questions, by the
way.

Next, check that the default route is present and correct. For that,
use:

	ip route show

or, if you don't have the `ip' command:

	route -n

If that all looks OK, ping the default gateway:

	ping -c 4 $GATEWAYHOST

then the IP of a known-good host such as iiNet's DNS server (I've never,
ever, seen it down, and it replies to ICMP ECHO):

	ping -c 4 203.0.178.191

If you get no response, try tracerouting that host. Use `mtr' if you
have it, otherwise `traceroute'. On Windows you can use `tracert' (seems
they took UNIX command naming to heart ... heh):

	traceroute 203.0.178.191

If you /do/ get a response, try using `host' or (preferably) `dig' to
resolve a hostname. On WinXP I think you can use `nslookup' but that's
only a vague memory; failing that use ping with a hostname.

	dig google.com

or

	host google.com

If that fails, check that /etc/resolv.conf is correct (Linux). Also try:

	dig @203.0.178.191 google.com

to see if you get a correct response from a known-good outside DNS
server (that you've already confirmed you can talk to at least with
ping).

If names resolve OK, try doing a manual HTTP request to a known-good
host using telnet (nfi how to force XP's telnet to use a non-default
port, so this is linux only):

	telnet www.iinet.net.au 80

you should see:

	Trying 203.59.24.221...
	Connected to www.iinet.net.au (203.59.24.221).
	Escape character is '^]'.

in which case type:

	GET /

If you get HTML, that's good. If not, well, something's wrong. Chances
are you will have hit the problem before this, anyway. Post here with
where it fails and the output up to the point it failed, and then we
might actually have enough information to attempt to diagnose the
problem.

-- 
Craig Ringer