device list - Routers

This is a discussion on device list - Routers ; Here's a question: How can a single wireless device (a laptop) on a LAN show up twice in the router's device list with two different IPs? Furthermore, the device in question was accessing the 3Mb/s Internet connection at 220K until ...

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Thread: device list

  1. device list

    Here's a question:

    How can a single wireless device (a laptop) on a LAN show up twice in
    the router's device list with two different IPs?

    Furthermore, the device in question was accessing the 3Mb/s Internet
    connection at 220K until I cleared (reset) the device list, whereupon
    the device was then able to connect at 2.7 Mb/s (all speed tests were
    run on dslreports.com).

    Can anyone explain to me how a single device managed to have two IPs
    assigned to it by the built-in DHCP server? BTW, the device was listed
    exactly the same except for the IP numbers. Does this kind of thing ever
    happen to WAN DHCP servers?

    TIA for any enlightenment.

  2. Re: device list

    bearclaw@cruller.invalid wrote:
    > Here's a question:
    >
    > How can a single wireless device (a laptop) on a LAN show up twice in
    > the router's device list with two different IPs?
    >
    > Furthermore, the device in question was accessing the 3Mb/s Internet
    > connection at 220K until I cleared (reset) the device list, whereupon
    > the device was then able to connect at 2.7 Mb/s (all speed tests were
    > run on dslreports.com).
    >
    > Can anyone explain to me how a single device managed to have two IPs
    > assigned to it by the built-in DHCP server? BTW, the device was listed
    > exactly the same except for the IP numbers. Does this kind of thing ever
    > happen to WAN DHCP servers?
    >
    > TIA for any enlightenment.


    Basically YMMV

    What IP address you get from a DHCP server depends on the server
    software. Some of them have "memory" and will reissue an IP address to
    a request from the same MAC address. Some of them don't and just give
    out the next IP address.

    One other factor: Most inexpensive wireless WAPs have their DHCP memory
    in RAM and the box could have been restarted.




  3. Re: device list

    Did you ever connect the laptop hardwired through the
    Ethernet port? If so, the router sees that as a different
    MAC address and will assign separate IPs.
    Mine does that.

    John Richards

    wrote in message news:bearclaw-459D78.21341806062007@news.supernews.com...
    > Here's a question:
    >
    > How can a single wireless device (a laptop) on a LAN show up twice in
    > the router's device list with two different IPs?
    >
    > Furthermore, the device in question was accessing the 3Mb/s Internet
    > connection at 220K until I cleared (reset) the device list, whereupon
    > the device was then able to connect at 2.7 Mb/s (all speed tests were
    > run on dslreports.com).
    >
    > Can anyone explain to me how a single device managed to have two IPs
    > assigned to it by the built-in DHCP server? BTW, the device was listed
    > exactly the same except for the IP numbers. Does this kind of thing ever
    > happen to WAN DHCP servers?
    >
    > TIA for any enlightenment.




  4. Re: device list

    In article <136f64g7h3mop51@corp.supernews.com>,
    Roy wrote:
    >bearclaw@cruller.invalid wrote:
    >> Here's a question:
    >>
    >> How can a single wireless device (a laptop) on a LAN show up twice in
    >> the router's device list with two different IPs?
    >>
    >> Furthermore, the device in question was accessing the 3Mb/s Internet
    >> connection at 220K until I cleared (reset) the device list, whereupon
    >> the device was then able to connect at 2.7 Mb/s (all speed tests were
    >> run on dslreports.com).
    >>
    >> Can anyone explain to me how a single device managed to have two IPs
    >> assigned to it by the built-in DHCP server? BTW, the device was listed
    >> exactly the same except for the IP numbers. Does this kind of thing ever
    >> happen to WAN DHCP servers?
    >>
    >> TIA for any enlightenment.

    >
    >Basically YMMV
    >
    >What IP address you get from a DHCP server depends on the server
    >software. Some of them have "memory" and will reissue an IP address to
    > a request from the same MAC address. Some of them don't and just give
    >out the next IP address.
    >
    >One other factor: Most inexpensive wireless WAPs have their DHCP memory
    >in RAM and the box could have been restarted.


    I would not expect the WAP to issue an IP address, unless the device
    requested one. If the device held a valid lease for that subnet, It should
    have used it, unless the device had been disconnected, in which case it
    should have requested it's previous address if the lease was still valid.

    If the WAP had been restarted, I would expect the ARP table to be flushed
    as well.


    --
    -- Welcome My Son, Welcome To The Machine --
    Bob Vaughan | techie @ tantivy.net |
    | P.O. Box 19792, Stanford, Ca 94309 |
    -- I am Me, I am only Me, And no one else is Me, What could be simpler? --

  5. Re: device list

    In article ,
    "John Richards" wrote:

    > Did you ever connect the laptop hardwired through the Ethernet port?


    No, the computer's owner is not technically adept. Wireless access
    looks akin to magic to her. I doubt she has any idea what the computer's
    ethernet port is for-- or any other hole on her box except maybe for the
    CD slot. She'd be like, "5 cats? What are their names?" Seriously.

    So far, the possibility of a short power outage sounds most likely.

    I still wonder how the device list duplication could so adversely affect
    her throughput, though. It seems obvious that was the problem, since it
    cleared up when I reset the list.

  6. Re: device list

    In article ,
    techie@tantivy.tantivy.net (Bob Vaughan) wrote:

    > I would not expect the WAP to issue an IP address, unless the device
    > requested one. If the device held a valid lease for that subnet, It should
    > have used it, unless the device had been disconnected, in which case it
    > should have requested it's previous address if the lease was still valid.
    >
    > If the WAP had been restarted, I would expect the ARP table to be flushed
    > as well.


    As fuzzy as my understanding becomes starting at this level of
    discussion, this is essentially what I would expect from router behavior.

    I guess without knowing exactly what went on beforehand, it would be
    pretty much impossible to diagnose the exact cause of the glitch. Still,
    if nothing else, now I have something new to look for when
    troubleshooting an apparently slow broadband connection.

    Can anyone think of a good reason NOT to reset the device list?

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