OS X Network Issues

Discussion in 'macOS' started by cppnerd, Jul 30, 2007.

  1. cppnerd macrumors newbie

    Joined:
    Jan 19, 2007
    #1
    Hi All,
    I recently moved to a new office and have been unable to use the wireless network there with my MacBook Pro and was wondering if anyone could help me with some pointers/ideas to try since I can't think of anything else.

    Airport will always get a self assigned 169.x.x.x address with its default DHCP detect even though I am connected to the network with the correct SSID/WPA. I have the router's IP and subnet and figured I would just override the autoDHCP settings with correct ones and give myself an IP address in the valid range of the router. Flushed all caches, reconnected, got my self assigned IP address but no internet/network connections. I manually put in the 2 DNS server IP addresses in the area in case that was the culprit, but that has not changed anything either. I've disabled firewall, have only one active connection to any network which is on the wireless (and have triple checked that), and I still can't get anything.

    Now naturally, you might assume it is a problem with the router--restart it/it's a Mac only problem/etc. The router has been restarted and that fixed nothing. The other strange thing is that I am the -only- computer that has any sort of problem with this network. There are a variety of Windows XP and Vista towers/laptops on the network, as well as a variety of Mac OS X computers (all 10.4.10 as well) including iMacs, MacBook Pros, and PowerBook G4s. My computer is an identical model to another MacBook Pro that has no problems--they were ordered around the same time and have the same network cards. My laptop has absolutely no issues on any other network I have ever come across.

    So I guess I really have no idea what I should do from here; I'm not very familiar with the BSD networking stack and how to troubleshoot any issues that cropped up. I've been through the system log files and have found no abnormal entries from when I have tried to connect to that network or any other.

    Does anyone have any other suggestions? I'm tempted to spend my day tomorrow reformatting and installing OS X again on here hoping that some setting that is messed up will be restored, but that is like using a nuclear bomb to kill a fly, and I would prefer to ask here since many here are experts with these kind of things.
     
  2. theBB macrumors 68020

    theBB

    Joined:
    Jan 3, 2006
    #2
    Shouldn't you let the base station assign you an IP address instead of picking a number yourself?
     
  3. GimmeSlack12 macrumors 603

    GimmeSlack12

    Joined:
    Apr 29, 2005
    Location:
    San Francisco
    #3
    From my experience whenever you get a 169.xxx.xxx.x IP address it means that something is wrong. You may be connected to the router, but the router might not be connected to the Net. Have you accessed the router through your browser? Released all connections? What router is it?

    I agree in getting an Auto-IP first. Later on try and assign yourself one. Reformatting will be a big waste of time.
     
  4. Sherman Homan macrumors 6502

    Joined:
    Oct 27, 2006
    #4
    Don't try to fix it with a static number. Many business class routers won't let a static address in the DHCP pool even if the number is valid. Stick with plain old vanilla DHCP if that is what everyone else is using. Make a new test admin user and see if that works. If it does, then you know you have a plist problem in your account. Since you can connect to other networks you know it is not a System or hardware problem.
     
  5. cppnerd thread starter macrumors newbie

    Joined:
    Jan 19, 2007
    #5
    Sorry I wasn't clear--letting the router assign an IP address fails (hence the 169.x.x.x addresses), but self-assigning didn't work either, and no errors are being logged on the system side. Nothing is being issued through the DHCP pool -only- to my computer. All other PC/Mac computers are being properly assigned IP addresses. I've been told the router's valid range of IP addresses has for sure more than 50 free IPs to assign, and bringing in other laptops has worked fine. (So there is a fine internet connection)

    Afraid there was no luck there either.

    This is a most bizarre problem. :confused:
     
  6. Celeron macrumors 6502a

    Joined:
    Mar 11, 2004
    #6
    Man, the amount of networking misinformation here in simply amazing. It seems while you are associated with the network it isn't actually communicating. Unfortunately what I would normally recommend here would be a sniffer capture, but with wireless that's increasingly more difficult.

    Assuming you are getting associated correctly you should be able to use Wireshark to see if you're seeing any traffic on the network. I use the Wireshark bundle located here:
    http://www.finkconsulting.com/page7.php

    You need X11 installed for it to work. On my Mac Pro I select interface en2, after which I can see the standard DHCP exchange if I disable and re-enable the Airport card.

    Alternatively you can try selecting the "wlt2" interface which will capture a subnet of 802.11 frames. I'm not very well versed in the details of said frames however you should be able to use them to determine if you are getting associated correctly.
     
  7. kwood macrumors 6502a

    kwood

    Joined:
    Jun 26, 2006
    Location:
    In the Great White North.
    #7
    Considering the network settings are something that is governed by System wide preferences testing in a new user of any type is a bit of a waste of time. Try removing this folder and following these steps:

    Launch Key Chain Access from the Utilites folder. Remove the network password from both the System and the Login keychain. Remove /Library/Preferences/SystemConfiguration onto your desktop and restart the computer. Then go into System Preferences>Network, create a new location and apply the changes. Attempt to connect to the network again with your appropriate DNS servers as provided by your network administrator.

    If this does not work then the wireless router will need to be reset (as in all the settings deleted and then recreated [holding the reset button for 30 seconds is usually your best bet]). You mentioned you restarted the router but I am unsure what you mean by this, in your case turning everything off, then back on (power-cycle) is not enough.

    169.254.X.X Always means there is a communication problem between two devices. In this case it is between the router and the computer. You can be connected to a router but not connected to the internet and still get a valid IP Address. This is done all the time for file sharing only purposes.
     
  8. GimmeSlack12 macrumors 603

    GimmeSlack12

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    Apr 29, 2005
    Location:
    San Francisco
    #8
    Glad to see you have such great advice for this guy too. Mr. "I don't know much about frames but I'll suggest them anyway". Leave the ego at the door.
     
  9. DoFoT9 macrumors P6

    DoFoT9

    Joined:
    Jun 11, 2007
    Location:
    Singapore
    #9
    you would really want to use DHCP so that it doesnt conflict with other clients. possibly the static IP you are using is already being used??
    make sure that the correct DNS server is typed in, you have the domain name identified, and that your main routers IP address is typed into the 'router' slot in network settings
     
  10. kwood macrumors 6502a

    kwood

    Joined:
    Jun 26, 2006
    Location:
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    #10
    On a similar note, if the network is set-up so you have to request a manual address, make sure the router is programmed with the IP you are requesting and your Airport card's MAC address (That is in System Preferences>Network changed "Show" to Airport, and it is the Airport ID).

    I second that motion. Besides the steps Celeron offered only work if they are connecting to the network with good communication. 169.254.x.x means there is a communication error, this is a standard whether is is Mac Windows or whatever you use.

    That and the steps provided do not make any sense for the OP's problem.
     
  11. Celeron macrumors 6502a

    Joined:
    Mar 11, 2004
    #11
    Actually, a sniffer will work just fine with a 169.x.x.x. address. Getting a 169.254.x.x address has nothing to do with a communication error. Its simply a DHCP autoconfiguration address when you can't get an address from a DHCP server. You may be communicating with the network just fine, however, your DHCP request packets may not be reaching the server, its reply may not be reaching your machine, or something else may be occurring.

    Again, you two clearly know little to nothing about actual networking, so before you blast me for not knowing the exact specifics of the 802.11 frames, maybe you should read up a little more on DHCP and the posters actual post, as he already mentions he can associate to the network without issue.
     
  12. kwood macrumors 6502a

    kwood

    Joined:
    Jun 26, 2006
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    #12
    You just proved my point, it's a communication error. If I call my girlfriend on the phone and we start talking but she can't hear what I say and I cannot hear what she is saying we have a communication error. I am not receiving her "packets" and she is not getting mine.

    I can call the phone company and have them run some test on the phone line (run this sniffer application) but that ultimately will not fix the problem. In this case we already know there is a problem with the way the computer is communicating with the router you do not need to run a sniffer application to verify that.

    It's just like if the screen on my computer has lines all over it and they flicker around and everything looks distorted. I do not need to run the Apple Hardware Test just to find out I have a problem with my video card. I know the problem is already there.

    EDIT: And yes I am aware that 169.254.x.x does not always mean there is a communication error. But it does in this case.
     
  13. GimmeSlack12 macrumors 603

    GimmeSlack12

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    San Francisco
    #13
    Just leave the ego at the door man. I wasn't the one who came in here critical of people's advice.
     
  14. DoFoT9 macrumors P6

    DoFoT9

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    Jun 11, 2007
    Location:
    Singapore
    #14
    i just wanna double check that u have added the domain name into the "DNS servers" in network settings...... under TCP/IP.
     
  15. Celeron macrumors 6502a

    Joined:
    Mar 11, 2004
    #15
    Way to highlight only one portion of my reply. Do you think it is not at all feasible that his particular laptop isn't SENDING any packets, thereby, no response would be generated? A packet capture on the interface would prove whether or not this was taking place.

    To use your own example. If you call your girlfriend and she cannot hear you, would it ever occur to you that maybe your phone wasn't sending any audio? It would be prudent in this case to put a device between your phone and hers to make sure you're actually sending the information you claim.

    Further to my point, if your monitor has lines all over it, why automatically assume it is the video card? Could it not be the monitor displaying lines all over it? Most certainly.

    Real troubleshooting works be eliminating possible causes until you arrive at the root cause, not throwing 1000000 darts at the board hoping one will hit the bullseye. This is akin to going duck hunting with a canon.

    Again, I believe a sniffer of the network to be the best option to begin troubleshooting.
     
  16. kwood macrumors 6502a

    kwood

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    Jun 26, 2006
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    In the Great White North.
    #16
    Well why don't we let cppnerd try the steps provided and see which one fixes it?
     
  17. cppnerd thread starter macrumors newbie

    Joined:
    Jan 19, 2007
    #17
    Thank you! This fixed the problem. :) I have no idea what the issue exactly was, as showing the keychain's saved WEP was indeed the correct one, but resetting this and rebooting and re-entering has fixed it. Just out of curiousity, does anyone here have any ideas as to why this would be? Do you think this was a problem with the router or has it ever been an issue with Mac OS? Was it just a really bizarre fluke?
    Thanks again!
     
  18. kwood macrumors 6502a

    kwood

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    #18
    The problem could have been that the password did not get properly entered or saved to either the keychain or the network preferences. Deleting the password from the keychain and removing System configuration (that is where most of the network settings are stored) allowed you start with a clean slate.

    In this case it was a problem with the preferences in the OS not the router.
     
  19. kwood macrumors 6502a

    kwood

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    Jun 26, 2006
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    #19
    Well I guess that settles this one Celeron. What was it you were saying about real troubleshooting again?
     
  20. Celeron macrumors 6502a

    Joined:
    Mar 11, 2004
    #20
    Just because my suggestion wasn't necessary to resolve the issue doesn't mean that it wasn't a valid troubleshooting step. Welcome to my ignore list. Its juvenile folks like you that make the Internet suck. Don't bother replying because I won't be able to read what you write.
     
  21. GimmeSlack12 macrumors 603

    GimmeSlack12

    Joined:
    Apr 29, 2005
    Location:
    San Francisco
    #21
    You can read what I write though.

    You brought it on yourself Celeron. So don't try and pawn it off on us being lame. Have fun with your hissy fit.
     
  22. kwood macrumors 6502a

    kwood

    Joined:
    Jun 26, 2006
    Location:
    In the Great White North.
    #22
    Come on folks lets not get our panties in a knot. What are we 12 years old here?

    The point I was trying to make is you do not need to run diagnostics when we already know there is a problem. Running diagnostics can be good if you do not know where the problem is, but in this case we already knew where it was.

    In short my point is there needs to be more time devoted to resolving the issue then running diagnostics trying to figure out that there is indeed a problem. I am not against running diagnostics and testing things out, but it is not necessary when you know where the problem is. This is my beef with a lot of fellow IT professionals. Not all are like this, but way to many are.

    EDIT: And Celeron, I am honoured to be on your ignore list, it's not every day I get put on there for helping someone else out.
     

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