Extending DHCP

[gazzanewpy]

How can I easily extend the DHCP range on my Win2000 network?

Is it simply by extending the scope?

We have two ranges available, one was meant for general usage whilst the smaller one was for administration. Due to system requirements we shifted all systems onto the general scope, leaving the other one spare.

Can we simply use the other scope alongside the first and still act as a single network?

 

[TechLad]

You can use different scopes...however you have to keep in mind such things as default gateway, name resolution options, obviously the easiest option would be to have 1 big scope (this assumes contiguous IP ranges), you can use 2 different scopes but do watch out for those options...

as an example this is a site i visit...

172.28.8.0/24
172.28.9.0/24
172.28.10.0/24
172.28.11.0/24

4 differente scopes, each has 172.28.x.1 as it's default gateway (where x is 8,9,10 or 11). Name resolution is provided via WINS (172.28.8.2) and DNS (172.28.8.3).

an alternative would be

172.28.10.0/22

1 scope with the a single default gateway of (172.28.8.1), the WINS and DNS servers would remain the same.

Hope this helps

Remember: Backups save jobs!!!
;-)

 

[Whoheard]

As long as there are no hops (routers) you are good to go.

Question.....

Are the scopes from the same network ID? Generally you cannot create two scopes with the same network ID. As a rule I use: 1 network 1 scope.

1 network meaning Network ID, i.e. 172.16.0.0/16

I know what I know and that's all I know.

 

[GlenJohnson]

More info on the setup would be nice. As you can see from the fine folks that awnsered, there are different ways of handling this based on your current configuration. Good luck.

Glen A. Johnson
"Fall seven times, stand up eight."
Proverb

Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884

 

[gazzanewpy]

Ok, we have been given two IP ranges for internal usage. The one has a subnet mask of 255.255.254.0 allowing us 512 addresses. The other is a standard 255.255.255.0, thus with 256. The two sets do not run concurrently. One runs 172.23.46.1 to 172.23.47.255, the other is 172.21.?? (I can't remember the last part of the network element).

We have now used 86% of the former scope whilst the other remains untouched.

Originally the site had virtually separated networks using IP as the method of separation (thus the two ranges). When we developed the new network we combined all systems under the one network - allowing us to use DHCP with all units without a complex method of delivering the right IP range.

However, we have now taken the network from 110 computers to 300 computers, 130 wireless laptops, network printers and wireless access points; all requiring an IP address. I could ask our supplier to widen our existing scope (I think) but what problems would I encounter? Or, I could use the other scope available to us and untouched but, again, what problems am I likely to encounter?

By the way, I am clearly out of touch since I have not seen IP addresses with the slash addition (172.16.0.0/16). What does the /16 mean?

 

[GlenJohnson]

16 stands for the number of bits on you're subnet mask.
1111111 11111111 00000000 00000000 = 255.255.0.0 which is a class b subnet mask.
I could ask our supplier to widen our existing scope (I think) but what problems would I encounter? I would suggesst with a network so large, go ahead and talk to you're supplier.

Glen A. Johnson
"Fall seven times, stand up eight."
Proverb

Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884

 

[ricpinto]

Glen is right, talk to your supplier if they are the one who gonna configure everything.

In addition above, /16 is CIDR the new addressing scheme, more effecient than Class A,B,C. Read this link

http://public.pacbell.net/dedicated/cidr.html

Possible solution:

Increase the number of hosts to 1024, /22 (mask 255.255.252.0) 172.23.44.1 to 172.23.47.254.


If you want to use the existing 2nd scope or you need another scope (different subnet, 512 hosts) let's say another /23(mask 255.255.255.254) with the range of 172.23.48.1 to 172.23.49.254 you'll need a router so that they can talk to your 172.23.46.0 network but the router should support DHCP relay agent (IP helper for Cisco).

http://www.microsoft.com/windows2000/en/server/help/sag_DHCP_und_RelayAgents.htm

We doesn't know how your network was setup, so you can ask your supplier opinion whether to use a big scope or use several smaller scope.

 

[Whoheard]

Your supplier can provide you with what you need; but, what about the other scope, 172.16.X.X. Why are you not using it? It would seem that it would solve your problem.


bob


I know what I know and that's all I know.