Using 'Start IP address' to limiting wireless clients

Discussion in 'Networking & Security' started by videobruce, Dec 5, 2017 at 3:58 PM.

  1. videobruce

    videobruce Limp Gawd

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    I hope I can explain this correctly, sorry if I don't. Some 'assumption' on my part is included.

    I assign static IP addresses to the clients, always have done so. Two Desktops, One Laptop, two DVR's one ATA (VoIP adapter) and now one 'Streaming box. All wired except a Laptop.

    Not a problem until I assigned one to this Streaming box (Fire TV 2).

    Looking at the attachments, specific the 2nd one, I assigned '31' (last segment/octet in the address) to the FTV. It showed correctly in that screen.
    When I looked at the LAN page in the Router, it the last IP segment/octet was '54' which is in the allowable 'limit range' I specified, not the static '31' I assigned in the device.

    Today, I now see it is showing correctly as '31' with what appears to be the former Router assignment (if that is the correct term) as '54' at the bottom of the page which I assume is a 'history' list.

    Can this behavior be due to "lease time"?

    When I initially connected the device to the Router, it was in auto assigned address mode. Can I assume the 'clock' started running at that point before I set a static address??

    I hope that made sense.
     

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  2. videobruce

    videobruce Limp Gawd

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    I just wanted to know if my assumptions etc. were correct or did I miss a few? :(
     
  3. Cmustang87

    Cmustang87 2[H]4U

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    Yea, I mean - you seem to have an idea of what you are asking, I think. Basically, when you connected the device to the network it requested an IP address via DHCP request and received one from the DHCP server.

    So, you basically used a lot of words to ask, "Does the DHCP clients sectionjust indicate the current active DHCP leases?" to which, the answer is yes. This just means that the DHCP won't reuse that IP address if another host requests an IP address until that IP has been released, which appears to be 1 day from the time it was requested. At that time, it will attempt to renew the IP address, but if the client has another IP address or is powered off, it will purge it... but if it's still on and in DHCP, it will renew the DHCP lease and maintain the same IP.
     
  4. videobruce

    videobruce Limp Gawd

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    I used the term "history" which you referred to "active DHCP leases". When those are entries are 'active' ,if you delete any of those in the box, what happens?

    Elsewhere, someone thought I was assigning the addresses thru thr Router which I do not, no idea where that conclusion came from as I thought I made myself clear.
     
  5. Cmustang87

    Cmustang87 2[H]4U

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    Assigning IP addresses through the router just means that you are creating static DHCP reservations to hold a particular IP address within the scope to only be used for a single MAC addresses.

    What 'active' means in this context is that the lease is active, but doesn't necessarily mean the client has current IP connectivity, or is even powered on. It just tells you the hostname and MAC address of the client who it is currently leased to. If you delete the entry, it manually releases the lease to be reused by another client via DHCP.
     
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  6. Chas

    Chas [H]ardness Supreme

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    If you want to limit who/what can connect, you have a couple options.

    If your router's DHCP server allows it, simply limit the range of IP addresses that are assignable.
    Router001.jpg


    Set your device registrations.
    Router002.jpg


    Router003.jpg



    Turn off guest networks and make sure you have a strong password on your normal wifi.
    Router004.jpg



    Also, turn on access control.
    Router005.jpg


    Now, I don't have enough experience with the Access Control to tell you if it'll block any devices signing on using statically assigned IP adresses.

    The Netgear site (using an R8000) says setting to "Block all new devices from connecting" blocks EVERYTHING (Wifi and wired) unless the MAC address is entered.
     
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  7. videobruce

    videobruce Limp Gawd

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    Interesting, but I tend to stay away from 'tweaking' inside the Router. Too many things to go wrong & too any confusing terms.

    I feel more comfortable navigating M$ Registry. (to a certain extent)
     
  8. Cmustang87

    Cmustang87 2[H]4U

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    Chas - I don't believe that's what the OP was looking for. I think they were only looking for an explanation of the terminology and how it happened.
     
  9. Cmustang87

    Cmustang87 2[H]4U

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    In a general sense, tweaking the Windows registry is orders of magnitude more invasive than making basic config changes on a router to have it do what you want - and by basic, I mean... these are some of the most basic functions of these routers for home. What are you doing inside your registry that you aren't comfortable doing in the router admin? Or, rather - were you just looking for clarification of the terms and execution on the router in the post, or do you have an end goal in mind that you are trying to resolve?
     
  10. videobruce

    videobruce Limp Gawd

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    Clarification would probably be the best way of putting it.
    I just wanted to know if my "assumption/understanding" after the fact was correct. But, that addition info doesn't hurt.

    I just used the Registry as an exaggerated comparison.
     
  11. Chas

    Chas [H]ardness Supreme

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    Then what specifically are you using when you created those screenshots?

    As CMustang said, doing registry tweaks on individual machines is ridiculously invasive. Especially when the tools you need are already available and straightforward (and easily reversible without having to look up instructions to undo what you initially did).

    I wasn't saying you had to use exactly what I have. Merely that you likely have the ability to limit access to known MAC addresses ALREADY. And if you're looking to prevent anyone else from simply hooking into your setup and assigning THEMSELVES an actual static address and partying, that is the way to go.
     
  12. videobruce

    videobruce Limp Gawd

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    I don't exactly understand your 1st question. Do you mean what device I used to access the Routers menu? if so, my main Desktop PC.

    I stated "navigating" the Registry, not modifying/editing. You never 'cleaned out' all the left over entries when you remove programs? Amazing just how many are left. I have found entries from programs I removed over 5 years ago still there.
     
  13. Dead Parrot

    Dead Parrot [H]ard|Gawd

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    To answer your original question, yes, lease time. Once the new gizmo got an address, it didn't ask for a new address until later. IIRC, it will ask for a new one a little before the lease expires. Until then, it doesn't care about the DHCP server. This keeps the entire network from grinding to a halt if the DHCP server goes offline for a bit, say during a reboot.

    When switching a gizmo from a pooled address to assigned, best to do a release/renew on the gizmo to verify you typed things correctly. Easy to fat finger MAC addresses.

    A corollary to this is a restarted DHCP server probably won't have a complete list of all clients until all leases have expired and the clients have requested and received new addresses.
     
  14. videobruce

    videobruce Limp Gawd

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    When you say the 'device', you mean within the devices internal menu, correct?
    If that doesn't have the ability, which many don't seem to have, then what?

    The release/renew function that is inside a Routers menu, isn't that, can't that be used?
     
  15. Dead Parrot

    Dead Parrot [H]ard|Gawd

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    Release/renew needs to run on the client gizmo. Or just reboot/power cycle/etc.

    1. Configure new gizmo to be a DHCP client. Check that it gets an valid address from your DHCP server.
    2. At the DHCP server, see what MAC the new gizmo has.
    3. Set the router to provide the desired IP to the MAC of the gizmo.
    4. Do a release/renew or equivalent on the client. Or just power cycle a simple client like a printer.
    5. Verify the proper address was obtained.

    Deleting a reservation from the table in the DHCP server won't automatically cause the client to drop its IP address. This can cause issues if you attempt to reassign the address to a new gizmo while the first one still has the IP. Assign at the server. Drop at the client.
     
  16. videobruce

    videobruce Limp Gawd

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    The release/renew within the Router, exactly what does that do?

    Isn't the default 'mode' for these 'clients' DHCP?