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General discussion

Strange Wi-Fi Network Problem

Aug 24, 2005 10:33PM PDT

I just bought an iBook G4 12 inch combo recently.

Machine Name: iBook G4
Machine Model: PowerBook6,7
CPU Type: PowerPC G4 (1.2)
Number Of CPUs: 1
CPU Speed: 1.33 GHz
L2 Cache (per CPU): 512 KB
Memory: 512 MB
Bus Speed: 133 MHz

I have no problem getting access to the Internet using Airport Wi-Fi at my uncle's house. Strange thing happens when I'm at college trying to use some programs (MSN, ICQ, Yahoo Messenger, Lime Wire, Xfactor, video streaming using Safari,etc...) All of these programs won't work, meaning the programs can't get connected to the Internet. I can only surf using Safari at the college but nothing else. And when I'm back to the hostel, the only programs that can get connected to the Internet are ICQ and Yahoo Messenger. I cannot surf. I've tried Internet Explorer, it's just the same - "...you're not connected to
the Internet..."
In conclusion, my iBook G4 can only surf at the college but nothing else. And back to the hostel, I can only chat using ICQ and Yahoo Messenger, and I can't do anything else that requires Internet connection. I've tried Adium. It doesn't work at the college but it works at the hostel for ICQ and Yahoo only. This strange problem occurs when I'm using Airport Wi-Fi only, I never try Dial-up or others. And the Wi-Fi indicator shows full signal, it says "You are connected to the Network xx. You are connected to the Internet via Airport." And the firewall is off.

When the programs can't get connected to the Internet, the dialog for each program says:

ICQ:
The server has closed the connection

MSN:
You may not be connected to the Internet

Yahoo :
"You have been disconnected from Yahoo Messenger servers."
This error may be due to a loss of your network
connection.Please check your connection to the Internet if
you are having trouble logging on to Messenger.

Safari:
Safari can?t open the page ?http://...." You may be not connected to the Internet.

The wireless card I'm using :-
Wireless Card Type: AirPort Extreme
Wireless Card Locale: Worldwide
Wireless Card Firmware Version: 401.2
(3.90.34.0.p13)

I've asked the staff at the college. The proxies all are not blocked. Other students who are using Windows OS can use MSN and chat without having any problems. The staff also told me that I do not need any password to access to the Wi-Fi at college.

I've also tried turning off and on the firewall and also changing the the proxies configuration in the System Preference>Network. Nothing worked.

Everything works fine at my uncle's house. I never changed any network settings since the first day I got my iBook. I just can't get "fully access" to the Internet via Airport at the college and hostel. This is so strange.

Hope someone can help. Thanks a lot.

Discussion is locked

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Just so you know.
Aug 24, 2005 10:59PM PDT

Many administrators lock down the network to such. Nothing may be wrong at all, but do ask the admin people if they allow such access.

Again, such is often shutdown to slow the spread of pests and virus.

Bob

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Take a look
Aug 25, 2005 12:51AM PDT

at the Network Pane in the System preferences. If you just single click the Network icon you will see a window that shows all the ways that you could be connected to the Internet. Built-in Ethernet, Airport, Modem, etc. Next to each one, on the left, there is a little indicator. Green is good, Amber is not. In the Airport line it should say that you're connected to the internet via Airport and that your IP address is xxx.xxx.xxx.xxx
Click Configure. You should be configured using DHCP and most of the spaces should be filled in. IP address, Subnet Mask, Gateway. The rest may be empty.
If your IP address starts with 169 there is a problem with the Wireless router.
Note what Bob said. Your system administrator may have the whole thing locked down tight.
The fact that you can surf at home but not at the hostel but can at college does not suggest a problem with the machine. More of a network configuration thing.

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Ports
Aug 25, 2005 7:25AM PDT

While I don't have a full answer to your problem, I think it has to do with open and closed ports.
Think of a port as a TV channel, and your computer as a TV. At your uncle's house you get all the channels, including HBO, Playboy, and pay-per-view.
A firewall is like parental controls. It turns off channels so that objectionable content can't get to your TV (attacks on your computer). Even if you turn off your firewall and open every port on your computer, the wireless router at the school and at the hostel will probably have their own, and it will be on.

Here's a link to a simple explanation of ports and firwalls.
http://www.faqs.org/contrib/articles2/Computer-Ports.html

Your web browser and mail program use port 80. All of the other programs you mentioned use various other ports to provide their services.
For example, according to my router's software, Limewire uses the gnutella port, TCP 6346, and MSN messenger uses two TCP ports, 6891 and 1863, also UDP ports 1863, 5190 and 6901. Video streaming uses a different port than your browser, which is why you can surf but not see video in your browser.

At your uncle's house you have access to all of the needed ports, and everything works.

At the college you have access to port 80, so you can surf, but none of the other ports are open to you.

At the hostel you have access to the ports for Yahoo Messenger (TCP 5000-5001 and UDP 5055).

The question I can't answer is why someone sitting next to you with a Windows machine has access to ports that you don't.
All of the numbers above came from my Belkin router.
Here's a link to a list of "well known port numbers"
http://webopedia.internet.com/quick_ref/portnumbers.asp

Hope this helps, it's a start.

Lampie

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No Advice, but...
Sep 4, 2005 12:08AM PDT

If it makes you feel any better, I'm at a a college too and also can't get on Yahoo with my Mac. A firewall seems like the most likely thing, right?

Maybe the Windows person is a dirty |-|@X0r.

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Solution...
Sep 4, 2005 12:13AM PDT
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The other solution called GAIM.
Sep 4, 2005 12:17AM PDT

GAIM from http://gaim.sourceforge.net/ is:

a. Open Source.
b. Runs on many platforms.
c. Actively being developed.
d. Security issues are taken seriously.

Cheers,
Bob

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Not Sure...
Sep 4, 2005 1:11AM PDT

...if that's going to help her, She never mentioned AIM, so I don't think ''Fire'' is her problem, She was/is locked out of ICQ and Yahoo at one location (actually it sounds like she's locked out of everything but port 80 there), At another location she can chat, but not surf port 80. She says she tried Adium, which is a multi chat software like GAIM, but that it didn't help.

I don't know if this will help, but in the ''sharing'' prefs pane, under the ''firewall'' tab is a button labeled Advanced. Click it, and there are options to use ''stealth mode'' and to ''block all UDP traffic''. Those settings may effect you differently while using different routers. It's a guess.
Also in that same window is the option to turn on firewall logging. The log may give clues, or not.

I can't think of anything that would cause this situation, so I'm just taking pot shots at it , if ya know what I mean.

If I was right, or if you figure it out, please stop back and tell what the answer was. This is like a mystery book with the last chapter missing!

Lampie

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The original poster is now missing in action.
Sep 4, 2005 1:29AM PDT

I noted GAIM since it's been the solution for IM across many platforms.

The original post was answered and the discussion is now careening off into possible other IM clients.

Bob

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Still finding a solution.
Sep 4, 2005 8:20PM PDT

Hey guys, I've just been busy with my homework and finding a solution. Lampie, I have tried what you've said about the ''sharing'' in Advanced thing, didn't work. Everything is just the same. Can surf, can't chat, can't get connected to any P2P file sharing programs like Xfactor and Lime Wire (at the college).

At the college, I've also tried filling in the DNS Servers tab, it didn't work. The DNS server IP was given by a friend and I suppose he got it from his ISP, and I filled it in and tried to see if I could get on Yahoo, ICQ, MSN, but it's just the same. I've also tried this at the hostel, didin't work aswell (can't surf, but can chat through Adium on Yahoo and ICQ but not MSN).
I've asked for the DNS server IP from the staff at the college, they said they don't know, and they just won't give it to me. Disappointed.
Perhaps if I had got the DNS server IP from the staff and fill it in and try it at the college, it would work, meaning I could probably get connected to ICQ,Yahoo or MSN, and also Lime Wire.

I've just updated the Adium to X 0.84, it just doesn't work at the college.

Oh, and I also tried sending a file and receiving a file through ICQ at the hostel, it didn't work, it closed the server and wouldn't let me send and receive the file.

I've just asked the person sitting next to me and played with her laptop for a while. Damn, she can get connected to everything including Yahoo Messenger, ICQ, MSN Messenger and surf without any problem. The only program Windows XP cannot use online is Lime Wire, obviously the people at the college do block only one poxy that is access for P2P file sharing.

This is so frustrating..and it's like a mystery, a puzzle that is waiting to be unraveled. Mac does seem to have something to do with this. It is definitely the Mac machine problem.
I'll keep updating this and tell you guys what the heck is really going on.
Thanks a lot for the help given by ya all.

Rene.

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Problem
Sep 4, 2005 11:36PM PDT

Bob/Lampie,

What would happen if her network administrator had the DHCP server set up to check MAC addresses as well. A local college here used that technique to prevent unauthorized access to their network. They have since dropped it as it was much too difficult to keep up with.
Could access to various ports be blocked in this way? If it is, and she has not "registered" her machine with IT, could this be the problem?

Just a thought

P

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You nailed it.
Sep 4, 2005 11:40PM PDT

So far, not enough clues to offer a solid answer. But you just did. Their IT may have filters and more in place to curtail use of the network.

If they don't call the IT staff/office, then they may sit in the darkness for a long time.

Bob

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Good one!
Sep 5, 2005 9:53AM PDT

It's the first plausable answer so far. If that's it, you get the Sherlock award!

If thats not the answer, it's got to be close.
Since we know the Mac works (at her uncles) the problem has to be at the router end. There are only a few ways for a normal router to selectively restrict access to wireless clients, and the only way it can tell one client from another is the Mac address.

Good one Pete!

Lampie

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Checked it with the network administrators
Sep 5, 2005 2:54PM PDT

I've just checked it with the network adminstrators at the college. They can't do anything about it.

First of all, they're only Windows experts they don't know about Mac at all.
Secondly, the DNS server IP that is given by my friend which I tried but didn't work, is actually the same as the DNS server IP the college is using. My friend's ISP and the college's ISP are the same. They are using the same DNS server IP.

As I have said, I have tried filling in the DNS server IP in the "DNS servers" tab, and it didn't work. It just doesn't work. I have tried several different DNS server IPs just to see what'd happen, they didn't work aswell.

And there is another problem that I have found out that is, when Safari tries to open certain pages like review.cnet.com, or news.yahoo.com, chat.yahoo.com (any site that is at Yahoo), it takes about 5-6 minutes opening the sites. And some sites can' be opened (logged in) at all. However, opening google.com takes just a mere second. The same to some certain sites, that take only a couple seconds opening and refreshing themselves.
I suppose this is because hundreds of students are using it that causes the Internet connection becomes slow that leads to this problem. Does it make sense?

Back to the mystery again, I have some questions. P mentioned about Mac address. Is it true that every wireless device has a unique ID called Mac address? Does it mean that if they enter my iBook's Mac address into their DHCP server, everything would work fine? There is a Mac filter, is it true? Does the Mac address only work if they have turned on the filter?
Now it just seems like this is the only plausible answer. Am I right?

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Hopefully
Sep 5, 2005 9:54PM PDT

Every ethernet device, regardless of where it is installed, has a unique MAC address. This is NOT short for Macintosh. It stands for Media Access Control.
Some places use the MAC address to identify who should, or shouldn't, be on their network. They can also control who goes where.
Without pointing fingers, I don't think this is a Mac v PC thing. I think it is a TCP/IP thing that your administrators should be able to sort out.
Try creating a New Location, in Network, setting ethernet to DHCP and see what happens.
Also, without telling us the rest of the IP address, what is the first set of numbers that you see in the IP address section of Network Preferences? It is directly below the line that says, Using DHCP. If it starts with 169. then the router is not talking correctly to your machine. If it is something like your friends, then I would go back to the MAC address thing.

Keep trying

P

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Finally..
Sep 7, 2005 3:34PM PDT

A guy who has a same iBook, also is having the same problem.

There is actually a content filter that is blocking port 5190 (the one ICQ is using), and port 5050 (the one Yahoo Messenger is using).
I've changed the port setting in Adium for ICQ and Yahoo accounts to Port: 80 (HTTP) and MSN Messenger to port 1863. Everything is working fine now.

At the hostel, port 5190 and 5050 is not blocked but port 80 is blocked.

Now this explains everything. And it doesn't have to do with the MAC address thing.

It's probably the network setting at the college here is different and it somehow affects the Mac users but not Windows users.

Thanks a lot for the help. I guess problem's solved.

Rene.

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Wow!
Sep 7, 2005 9:43PM PDT

How very bizarre.
However, I'm glad you finally got to the bottom of the problem and can now surf at random.
Congratulations on your perseverance.

Bob, is it possible to configure the DHCP server to supply the necessary information AND to open and shut ports as desired?
Strange that it should only affect Macs though.

P

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PC ports
Sep 8, 2005 12:44PM PDT

My question is, what ports does Windows use for Yahoo, ICQ, etc.?
The port numbers for most of this are standard across the board, or so I thought.
Maybe Windows has a way of switching ports if it finds one blocked?

Lampie