[Web4lib] Advice? PCs will connect to LAN but not internet

[Andrew Mutch]

Beth,

This is probably outside the scope of the Web4Lib list but since I know
the pain of networking troubleshooting, here's a few things to try:

1) Check your network configuration on the problem PCs

The easiest way to do this:

Start - Run - type in 'cmd' (no quotes) and press enter

You'll then see a dos-style command box.

Type in: ipconfig /all

That should list the computer IP and DNS Server address. Confirm that the
correct addresses are showing. Compare it against a working computer to be
sure. When "I can't connect to the Internet" isn't due to a hardware
problem, it's usually caused by a problem with the network settings, like
the DNS server.

2) Confirm network connectivity

You want to check that your computers can actually get beyond your
firewall. From the same command box, type:

ping www.yahoo.com

You should see something like:

W:\amutch>ping www.yahoo.com

Pinging www.yahoo-ht2.akadns.net [69.147.114.210] with 32 bytes of data:

Reply from 69.147.114.210: bytes=32 time=167ms TTL=51
Reply from 69.147.114.210: bytes=32 time=166ms TTL=51
Reply from 69.147.114.210: bytes=32 time=158ms TTL=51
Reply from 69.147.114.210: bytes=32 time=159ms TTL=51

Ping statistics for 69.147.114.210:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 158ms, Maximum =  167ms, Average =  162ms

If you see this, you know you have at least basic connectivity established
[some firewalls block this traffic so if the site times out, try it on a
working computer].

If you get "host unreachable", that's likely due to a physical problem
like a bad cable or switch. If you get "unable to resolve host" or
something similar, the problem is that your computer can't talk to the DNS
server. Double-check the DNS settings.

3) Establish browser connectivity

If you can reach Yahoo using a Ping, your browser settings might have been
changed (malware/spyware can cause this). Open up your browser and check
to see that proxy settings haven't been set or changed (does all your
traffic run through the content filter?). In Internet Explorer, it's
located here:

Tools - Internet Options - Connections - LAN Settings - Proxy Server

Again, compare them against a working computer. If they've been changed,
change them back and see if that gets you going. If you use Public Web
Browser or a similar browser replacement, the settings are determined by
IE. If you use Firefox, it has similar settings in the
options/preferences.

I would start with your staff computer as you'll have less variables do
deal with in troubleshooting. Also, changing network settings will require
Administrator permissions so log in with an Administrator-level user
account.

A couple other items to try:

a) Change the port that the staff PC is plugged into.
b) Change the network cable connecting the staff computer to the network

These probably won't make a difference but sometimes the problem can be as
easily resolved as this. I can't guarantee that any of the above will fix
the problem but it will help narrow down the scope of the problem and at
least address basic networking problems.

Also, while it seems like the problems are related and they may very well
be, don't assume that's the case. Sometimes it's just coincidence that
computers start acting up at the same time. You want to avoid overlooking
solutions just because it doesn't necessarily fit your assumptions.

Good luck!

Andrew Mutch
Library Systems Technician
Waterford Township Public Library
Waterford, MI





>
> I'm having a problem over here and I can't figure out what's going on.
> Recently we got in six new PCs, set them up and put them out for the
> public.
> We have had no problems with them until now.  Around the same time we got
> in
> a new one for a staff member.  We also have four "old" PCs that were set
> up
> with security so they'll only access the library catalog over the
> internet.
>
> These computers are unable to access the internet as of this morning.
>
> They are on the network, can see other computers on the network, they just
> can't get to the internet.  The staff computer has a 172.16.2.X address,
> the
> public ones are all 172.16.3.x.  Other PCs in both ip ranges can access
> the
> internet with no problem.
>
> The staff computer is plugged into a different switch than the public
> computers.  Other computers on both of those switches are not having a
> problem.
>
> While all of the public computers are secured with Microsoft Shared
> computer
> toolkit, the staff computer is not.  While the six new public computers
> and
> the one staff computer are the same Dell model, and arrived at the same
> time, the four catalog computers are older ones.
>
> I cannot figure out what they have in common, or why they are unable to
> access the net.  Can you think of anything to check?  I have looked at the
> firewall, but no changes have been made recently, and I also looked at the
> content filter, but again, no changes lately.
>
> Thanks for any help you can offer.
>
> Beth DeGeer
> Assistant Director
> Bartlesville Public Library
> 600 S. Johnstone, Bartlesville, OK 74003
> (918) 338-4164 bdegeer at bartlesville.lib.ok.us
> http://www.bartlesville.lib.ok.us/
>
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