Identifying cat5 cables on router question

Discussion in 'Server Networking' started by Bryce, Jan 3, 2005.

  1. Exactly,... that is the "now if records exist" part of my comment.
    Phillip Windell, Jan 6, 2005
    1. Advertisements

  2. No, it wasn't "which RJ45 port" is was "which cable". This is from the
    original post:


    Knowing the IP#/MAC of the machine and which switch port it is connected to
    isn't going to help at all if you don't know where in the building that
    particular IP/MAC is physically located. If they didn't bother to lable the
    cables, they probably never kept records of where the machines (IP/MAC) were
    physically located. Then if DHCP is used the IP# would be useless and you'd
    have to depend on the MAC (as Jeff said), what is the chance they
    documented where every MAC was physically located and kept it updated over
    time if they never bothered to label the cable to begin with?
    Phillip Windell, Jan 6, 2005
    1. Advertisements

  3. How is a testing tool going to tell you which Floor/Room/Walljack the cable
    goes to on the other end? The device cannot know that. See my other
    post,..this is about the cables having no lables and not knowing the "runs",
    not about which IP/MAC is using which switch port.
    Phillip Windell, Jan 6, 2005
  4. We can all make assumptions. What makes your assumption
    right and mine wrong?

    Okay so you assume a computername is not sufficient to know
    which computer is connected to each cable. To me that is more
    than half the battle. With the computername you can determine
    which user is logged into which machine. Now are you going to
    assume that knowing the particular user isn't going to help you
    determine the computer location.

    I don't follow you with this DHCP concern of yours.. Perhaps you
    can elaborate? I've got computers on my lan which have had the
    same address since the lan was built in 1997.

    Michael Giorgio - MS MVP, Jan 6, 2005
  5. Now your assuming there are open jacks as well?
    Michael Giorgio - MS MVP, Jan 6, 2005
  6. Whatever...the OP has the material from both of us,..he can do what he
    thinks is best.
    Phillip Windell, Jan 6, 2005
  7. Of course. It is the *cables*,... the physical cables,...he is trying to map
    out and label them,...whether they have machine running on them or not.
    Maybe they all have computers on them, maybe they don't, most place
    they won't.

    Geesh,...fighting over this is just plain silly.

    From first post.....

    Notice?,...cables,...not machines,...*cables*

    Come'on,..It's a 3 story building! Do you really think they only ran exactly
    the same number of cables through the walls as the exact number of machines?
    Do you think you only forgot to lable to ones with computers, but remember
    to lable the ones without computers?
    Not all cables in the building would neccessarlily have machines running on
    them and they may not even be plugged into the switch (patch panels,...patch
    cables,...not all may have a patch cable connecting the to a switch). Many
    buildings have more cable runs than are actually used and any given time. If
    there is nothing connected to a cable you can't map it sitting in the
    Admin's chair, you have to track it down with a Fox & Hound or similar tool.

    I don't understand why you are wanting to fight over something that seems so
    Phillip Windell, Jan 6, 2005
  8. Agreed.

    Michael Giorgio - MS MVP, Jan 7, 2005
  9. Fighting? Hmm I didn't see it that way.
    In any case have a good day Phillip. :)
    Michael Giorgio - MS MVP, Jan 7, 2005
  10. Bryce

    Brian Guest

    Bryce, I'm not a technical gunius like the rest of thest guys, but this may

    I run Cisco switches, but I assume an intel switch will give you the mac
    addres connected to your port.

    step 1. download a list from your switch with switchport and MAC address.
    Use free kiwi cat tools.

    step 2. use a vbscript to list all IP and associated MAC's on your network.
    If you have DNS or DHCP, all the better. You can export a list of IP's with

    step 3. use either excel or access to list these. One for IP's run from
    your network and one for the switch download. Match the two tables via MAC
    this will give you which IP is associated to which switch port.
    step 4. go to the switch and trace each cable from your patch panel to your
    switch port. (hoping you have a labled patch panel). it path port 1 to
    switch port 16 and so on.
    step 5. take this list to each PC. identify each ip on each pc and get your
    patch panel port number from your list.

    Sounds like a lot of work, but actually, going to each pc is the hardest
    part and and marking each wall port.

    this save you from spending money.

    Hope this helps.
    Brian, Jan 17, 2005
  11. Another way to do it this would be to tone it out using a meter. I use a
    fluke meter but there are many different alternatives.
    Eugene Taylor, Jan 17, 2005
  12. Bryce

    Brian Guest

    I agree, the recommended footwork gives you documentation you can use for
    inventories, security analysis, etc.

    Tone generators are good for quickies.

    Brian, Jan 17, 2005
  13. Tone generators would not be good for "quickies" but it is the right way and
    the best way to do it. There are two pieces to them and someone has to walk
    to the other end of the cable to clip it on. The piece that generates the
    Tone is moved from wall Jack to wall Jack while the Sensor is passed over
    the Patch Panel or cable ends in the Wiring room till it pickes up the
    signal,..the cable is then physically labled and you move to the next wall
    Phillip Windell, Jan 18, 2005
  14. Bryce

    Bryce Guest

    Well, I've spent almost two weeks on it. And you are correct, many of the
    cables don't even patch in so I can't simply use a tester and go look at the
    little blit on a switch or router because it may or may not go there
    anyways. It's been quite an experience. I think I've got about 20% of it
    mapped out so far. If they had just put in the extra few hours to write
    things down.
    Bryce, Jan 24, 2005
  15. Bryce

    Bryce Guest

    Of course, this is only working if it was patched in somewhere.

    It seems that some of these cables really go nowhere!

    Some of the cat-5 jacks in the walls have no wires going into them, or a 4
    port jack may only have 2 cables going into it.

    So someone plugs something into the wall, assuming that it is live, and they
    think there is something wrong with the printer or the laptaop, etc... but
    really, it's because there is nothing live in the wall.

    I've had countless people think that they have the wrong ip address on a
    printer, or whatnot, spending hours of time trying to figure it's settings
    out, then I show them that they are really plugged into nothing because they
    have too few ports next to their patch panels in some of the mech rooms....
    so the previous guys didn't plug them all in.

    They are in shock, really. As am I... It's good job security, but on the
    otherhand, it's quite a waste of overhead currently from a business
    standpoint. I should bring the previous guys in and have them shot!
    Bryce, Jan 24, 2005
  16. Then you first pass the sensor over the one end of the cable that you
    already know about (without the tone generator). If there is "power" in the
    cable the Sensor will pick up the "buzz" in its speaker. Find equipment
    with "connection problems" and unplug them one at a time untill the "buzz"
    quits, you know where the cable goes, assuming there weren't any hubs
    or switches in between to keep the "buzz" going. If you aren't confident
    that the Sensor would pick up the power "buzz" on the cable, then just patch
    it into a running hub or switch and see if the LED lights up, if it lights
    up then the is something on the other end, if it doesn't, then there
    probably isn't.

    If there was no "power" on the cable, clip the tone generator to it, then
    start tracing the lenght of the cable using the Sensor, will pick up
    the tone from the Tone Generator by just being close to the cable and gets
    louder as you get closer. It is going to take time to get it all done,..but
    it isn't like you have a choice, has to get done.

    In my experience, once it is all mapped out, it isn't as big a mess as you
    think. It always seems worse when you aren't sure what you are looking at.
    Make sure you lable as you go, maybe even temporary lables like "string
    tags" so you can alter it if you make a mistake,...use permanent lables when
    you know it is correct.
    Phillip Windell, Jan 26, 2005
  17. The Fox/Hound Tool has to work on a disconnected cable that has no power on
    it, so if they don't go anywhere that is just fine. See my other post for
    I work at a ABC affiliate TV station with around 100 units. I drove a
    semi-truck for 10 years, got out of the truck on Friday and started here on
    Weds with nothing more than "hobby experience", one simple certification,
    and a GED (dropped out of HS second year). I was the assisant to the Admin
    at the time,...he left 6 weeks later leaving an 75% finished system behind.
    I wasn't even sure where all the rooms were let alone anything else. But I
    survived,...5 years later I'm still here and things work well enough that it
    gets boring around here most times,...that's why I have the time to spend in
    these groups.
    Phillip Windell, Jan 26, 2005
  18. Bryce

    Todd J Heron Guest

    Nice story Phil.
    Todd J Heron, Jan 27, 2005
  19. That was back just before we were all hanging out in the old Proxy2 group
    before ISA2000 came out,...when you were known as "ZZZZT" if I remember
    correctly :)
    Phillip Windell, Jan 27, 2005
  20. Great story. Similar to mine but I made it through HS.. <g>

    BTW I have to replace our old cat 5 with cat 6 cable in the
    office and the first item I purchased is a tone generator to
    help although I know where most of the cables go because
    of the switch report. I have some dead runs I'd like to remove..
    Michael Giorgio - MS MVP, Jan 27, 2005
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.