dhcp server

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sid kant

Joined Dec 16, 2010
13
does a dhcp server has a range of addresses it can allocate? if a client has a static ip address within that range, what does the dhcp server do? can u assign a dynamic addres to a client that has a static addres?
 

nerdegutta

Joined Dec 15, 2009
2,684
Normally you give the DHCP-server an ip-range, of the class C-type network. This is for a local network.

For instance,

DHCP start: 192.168.1.50
DHCP stop : 192.168.1.99

Now you have told that the DHCP has 50 available addresses.

My experience is that if there is a static ip, say 192.168.1.68, the DCHP, treats it as if it has assigned it itself.

Or something like that....:rolleyes:
 

shteii01

Joined Feb 19, 2010
4,644
Most of your questions are just Google-Fu so I will answer the last one.

Clients on a network need some way to be identified from other clients, think apartment numbers in the apartment building. IP address serves this purpose. Each client on the network has unique IP address. Each client only need one address. Trying to have a client that has a static and dynamic address is very very stupid because it is completely unnecessary.

In case you are trying to hide your "tracks", remember that in addition to IP address you also have a MAC number. IP address can be changed using dynamic system of assigning IP addresses. MAC number can not be changed, it is wired into the device, it is hardware, not software.
 

subtech

Joined Nov 21, 2006
123
does a dhcp server has a range of addresses it can allocate?
Keep in mind that the following is given in very generic terms and simplified greatly.


Yes, it is always desirable(actually mandatory) to limit a DHCP server to a specific range of addresses that it may issue. One must remember that in IPv4, there are over 4 Billion legitimate addresses that could theoretically be issued. It is necessary to manage networks carefully if one expects proper and reliable operation.

if a client has a static ip address within that range, what does the dhcp server do?
In short, it takes notes. Here's how it works.

When a host on a network is configured to get it's IP address automatically, upon startup it sends a broadcast out on the local network that says in effect " hey, I'm new here and I don't have an IP address yet. My MAC address is XX:XX:...... Can someone issue me an IP address?"
The DHCP server on this network will respond and offer an IP address to the host. The host will normally accept the offer and respond with a confirmation.
This exchange is often referred to by network geeks as a "three way handshake".

If the host is configured with a static IP address however, the scenario goes something like this:
"Hello everybody, I'm new here on the network, my MAC address is XX:XX:XX......
AND my IP address is 192.168.1.100. If anyone has data for me, here I am."

The DHCP server on this network has heard this broadcast, stores that IP address in its table of addresses, and will NOT issue that address to any new hosts that appear on the local network and ask for a network address via dhcp.

One thing you should know however, (and many people don't believe this) is that if your computer needs to communicate with another computer on the same local network,
IP addresses aren't needed or used. Hosts on the local network learn their neighbors
MAC addresses and use them for communication.
IP addresses are used when information from your host machine must leave your LOCAL network (via a gateway,or router) and find its way to a host on a different
network.

can u assign a dynamic address to a client that has a static address?
For all practical purposes, no.(I'll not get into virtual hosts, etc.)
Your network adapter has only one MAC address and is allowed one IP address per port.
If the adapter is configured with a static IP address, it should not broadcast a request for issuance of another IP address.

By the way, as previously mentioned,
Google is your friend.

You don't have to be crazy to want to work in networking.


But it sure helps


Hope this helps. :)
 
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