Connection issues on a laptop

Discussion in 'Wireless Networking' started by Gerald Vogt, Aug 11, 2006.

  1. Gerald Vogt

    Gerald Vogt Guest

    On my ThinkPad laptop I have a builtin a/b/g WLAN card. I now have a
    D-Link WLAN router here to which it will properly connect but most TCP
    connections will fail: the computer sends a SYN but never receives an
    answer. This is the case with HTTP, IMAPS, POP3S to all servers I have
    tested (unlike the usual MTU problems when connections to some servers
    will work).

    pings will work, though. A ssh with putty to one server on which IMAPS
    fails does work also (this was the only TCP connection I have found
    working through that wireless card and router). I have tried various MTU
    settings for the WLAN interface but it does not make any difference.

    When I use a Linksys WPC PC-Card everything works fine (with default
    MTU). I have compared all settings in property pages and in the registry
    for both interfaces but I cannot find any relevant difference.

    The builtin card works fine with other access points and hot spots.

    What else could cause these kind of problems?

    Thx, Gerald
    Gerald Vogt, Aug 11, 2006
    #1
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  2. Hi
    MTU is a matter of the type of the Internet connection that you are using.
    Set it once and it should be OK (
    http://www.ezlan.net/Internet_Speed.html ).
    Given your description it seems that there is some mismatch between the
    Wireless Client, and the Access Point. Try it straight forward with No
    Security and NO special settings (like ssh, VPN etc.)
    My New Wireless does not work - http://www.ezlan.net/wireless.html
    Wireless - Basic Configuration: http://www.ezlan.net/Wireless_Config.html
    Wireless Security - http://www.ezlan.net/Wireless_Security.html
    Jack (MVP-Networking).

    "Gerald Vogt" <> wrote in message
    news:uY4%...
    > On my ThinkPad laptop I have a builtin a/b/g WLAN card. I now have a
    > D-Link WLAN router here to which it will properly connect but most TCP
    > connections will fail: the computer sends a SYN but never receives an
    > answer. This is the case with HTTP, IMAPS, POP3S to all servers I have
    > tested (unlike the usual MTU problems when connections to some servers
    > will work).
    >
    > pings will work, though. A ssh with putty to one server on which IMAPS
    > fails does work also (this was the only TCP connection I have found
    > working through that wireless card and router). I have tried various MTU
    > settings for the WLAN interface but it does not make any difference.
    >
    > When I use a Linksys WPC PC-Card everything works fine (with default MTU).
    > I have compared all settings in property pages and in the registry for
    > both interfaces but I cannot find any relevant difference.
    >
    > The builtin card works fine with other access points and hot spots.
    >
    > What else could cause these kind of problems?
    >
    > Thx, Gerald
    Jack \(MVP-Networking\)., Aug 11, 2006
    #2
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  3. Gerald Vogt

    Gerald Vogt Guest

    Jack (MVP-Networking). wrote:
    > Given your description it seems that there is some mismatch between the
    > Wireless Client, and the Access Point. Try it straight forward with No
    > Security and NO special settings (like ssh, VPN etc.)


    It is a plain simple open access point with no security setup. There are
    no special settings. Both wireless cards use WZC and the network
    configurations are identical. There is no firewall nor does the router
    have any special settings. Both cards send the same SYN packets with MSS
    1460 when trying to establish a TCP connection. The one card receives
    the SYN,ACK the other not.

    I can ping servers in the internet. I can connect to a SSH server with
    putty and I can use a cisco vpn client to tunnel via IPSEC/UDP. putty
    does the same kind of TCP connection and succeeds.

    Thx, Gerald
    Gerald Vogt, Aug 12, 2006
    #3
  4. Gerald Vogt

    mrkate

    Joined:
    Aug 23, 2006
    Messages:
    1
    I'm having the same problem -- did you figure it out? The weird thing with mine is that when I connect my laptop into my wireless router directly with a cat5 it works, but when I try the wireless, I can ping ips and urls (so I know DNS is working) but can't access any websites via the browser.
    mrkate, Aug 23, 2006
    #4
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