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DHCP

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darronb

Technical User
Feb 8, 2002
67
GB
I am currently studying for my CCNA and doing a project that has a small portion of DHCP in it.

I know little about DHCP, could anyone give me any pointers.
Links to an Understanding DHCP

My specific question is:-

Is it possable to set DHCP to allocate just a smmall range of IP addresses?
 
You can control many aspects of DHCP. You can set up a scope, or a pool of IP addresses to be handed out to clients. You can also create exclusions....these are IP addresses that will not be given out....they are usually static ip addresses of network printers and servers. In addition, don't ever forget that once you set up DHCP, set up your scope and scope options as well as any exclusions, you must authorize the DHCP server in order for it to start handing out IP addresses. This is to prevent any unauthorized DHCP servers on the network, as even the slightest mistake can bring your network to its knees. If a client cannot contact a DHCP server, it will most likely end up with an APIPA address, (Automatic Assigned IP Address), which is in the range of 169.254.0.1-169.254.255.254.
 
Real world tip for you (post CCNA theory!)

Don't forget that DHCP will NOT route across CISCO boxes by default, you'll have to turn it on (beware switches as well). Common mistake, costs many an hour troubleshooting the wrong thing, especially if you start getting into RIS or PXE booting - I know, I've been there wasting that time!

Good luck with your CCNA

RosieBsDad
 
On this subject I have just had a friend come to me with a W2000 notebook that cannot obtain an address from the DHCP when on a lan. Also when manually asigning all address's including DNS, ping will work even to the internet (ie can ping DNS) but cannot ping doman names ( If dialup to ISP the PPP adapter with resolve an address but again cannot resolve domain names. After 2-3 hours I suggested reinstallation of W2000. Anybody got a less drastic idea
 
CliveM - whats the netbios over TCP/IP setting for the LAN connection (lan connection properties, TCP/IP properties, advanced button, WINS tab)?
 
CliveM - if you haven't already been there, you need to be looking at NSLOOKUP (or one of the shareware/freeware tools such as Sam Spade), th sshould help you with your DNS issue.

However, if you have a DHCP issue as well, I suggest you try to resolve that first - one may well fix the other....

RosieBsDad
 
I have 50 class rooms with 48 network connections in each. giving me a total of 2400 network connections needing IP addresses.

I need to do this using DHCP, is it possable?

If so is it possable to divide these IP addresses down into subnets.

If so how does DHCP do this.

Does this have any effect if VLANS are used.
 
If it is a routed network, you can configure your router as a DHCP relay agent. By default, routers do not forward broadcast traffic, (DHCP is broadcast traffic). If a router is configured to be a DHCP relay agent, it will forward DHCP requests but ignore all other broadcast traffic.
 
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