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DHCP Reservation vs Static IP Addresses

By kcrouse96h
Aug 5, 2010
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  1. I have about 20 devices on my home network, half computers and half stuff like TVs, blu-ray players, xbox, etc. Most devices are connected by ethernet cat6 wire, but some of the PCs connect wirelessly. When I look at the device list on my router’s website, the computers are listed as their computer names, but several devices are named "unknown." These are my TV, Blu-ray player, etc. I can reserve an IP address in the DHCP section for each of them (i know their macid's) and type in the proper name. All of this can be saved in my router. That way, I can see all my devices listed by a real name (not "unknown"). This will allow me to identify any rogue devices that might sneak onto the network since they would be in the dynamically assigned section.

    Questions:

    Is it problematic to do DHCP reserving as a general practice? It seems cleaner to me, especially if the devices will be plugged into the network 24/7.

    When I reserve the DHCP address for a device, will the router automatically assign the new reserved IP address when it sees that particular macid coming online? I don't have to set anything on the device itself, right? (except for the device to receive an IP address automatically, which is usually the default)

    I have a printer that I have currently assigned a Static IP address (inside the printer). I can put this address outside the DHCP range and leave it static (as it is now) or I can put it inside the DHCP range but reserve the address. Is there any difference or preference?

    My configuration is:
    Motorola cable modem -> dlink DIR-825 router -> dlink 24-port gigabit switch.
    then off the 24-port switch are: dlink DAP-1353 wireless access point extender, 5-port dlink gigabit switch

    I DHCP-reserved an IP address for the 1353 access point. I also gave it a separate ssid and different channel. Two computers connect wirelessly to this access point. One computer is a bit sluggish from time to time, but i think the set up is ok. However, anything special I need to do with the 2 switches? Or are they just routing traffic. Do switches have macid's? Ok, I'm really showing my ignorance now.

    Thanks!
     
  2. jobeard

    jobeard TS Ambassador Posts: 9,330   +622

    BINGO :)

    I use this technique too and just love it.
    Known systems&devices (ie their MACs) are reserved for specific IP addresses,
    creating the same effect as if I had a Domain Controller handing out Static addresses.
    NO system is not manually configured so that the laptop can still travel and use DHCP anywhere.

    Personally, I set the known systems 2-10 and the guests get assignments 11 and above.
    WHY? so that I can assign Firewall Rules for the know vs the unknown and let friends attach to my
    router without any concerns for unauthorized (ie unintentional infections) access.

    Works just great, albeit, my Netgear router will only reserve 10 slots.

    [hint: I have 6 devices so I fake the MAC addresses for the other four :) ]
     
  3. jobeard

    jobeard TS Ambassador Posts: 9,330   +622

    read the above post

    @kcrouse96h
    Less work to place any existing static ip devices OUTSIDE the dhcp range as it has already been configured. HOWEVER, if you want all configuration controlled in one location, go for the MAC reservation :) Just be sure you have 20 slots for the MACs; mine only has ten.
     

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