How to get more IP's

[jmair]

I’m an Administrator in a small district with nobody to discus tech questions, and stumbling onto your Forum/Site has been a godsend. Thanks for being here!

 

Ok, the question.

 

We run all Windows 2003 and XP pro machines.

Currently our ip range is 10.1.1.1 – 10.1.1.254, but would like to go to the High School machines and make them static to 10.1.2.1 – 10.1.2.254.

Where would I go to make these IPs work on the network? In DNS I’ve added a new Subnet for 10.1.2.0 – 10.1.2.254 in the reverse Lookup, but that didn’t work.

Any help would be excellent.

 

Thanks.

[FN-GM]

why are you making them static and not using DHCP in sevrer 2003 to give the addresses to the clients

[Ric_]

You will need to edit the network settings manually on each machine and give them new IP addresses.

 

You should undo the changes you made in DNS... this is wrong.

 

You will also need to make sure you get the subnet mask right (255.255.254.0 should do although I'm no expert here).

 

You may find that some kind of script would be helpful if you have all those computers to sort.

[jmair]

I'm using DHCP for other machines, but my firewall only lists IPs, not computers, and for easy reading I wouldnt mind knowing what machine is located where.

 

If my DHCP scope is from 10.1.1.1 to 10.1.20.254, shouldn't i be able to set a client with a static Ip of 10.1.x.x manually and it should work as well as a static IP of 10.1.1.x ? For some reason it's not, and I cant figure out why.

 

To ensure that the subnet isn't an issue, it is 255.255.0.0 (unless this is the cause.)

[FN-GM]

what OS are you using for DHCP?

[jmair]

what OS are you using for DHCP?

 

Windows Server 2003 , all machines are XP pro

[FN-GM]

ok in the DCHP there is something what you can set static ip addresses to computers it works using the computers mac address

[mattx]

The subnet is ok, why not just keep the scope and make the address lease unlimited ?

[localzuk]

Try making use of address reservations on the DHCP server. Means you can centralise it and not have to go to each machine, but each will have a static address.

[timzim]

You can set up reservations in DHCP so that each mac address always gets a particular ip but, if you're doing that for your entire network, I don't see the point of using DHCP as it's not exactly being 'dynamic' is it?

[localzuk]

The point would be that should you need to change the address or range or anything, you can just do it on the server rather than wandering round to x number of computers.

[jmair]

The problem I'm encountering is, Dynamic or not, I'm stuck with less than 250 cleint machines.

 

Any Ideas where I can look to broaden my range? I'm pretty sure my scope is fine.

 

 

Hope this helps some. Let me know if there is anything else that may help and I'll post a shot also.

http://www.parkcountyre2.org/images/dhcp/dhcp1.jpg

 

http://www.parkcountyre2.org/images/dhcp/dhcp2.jpg

[Joedetic]

Well for a start you're using a class A IP address. So your subnet mask would be something along the lines of 255.0.0.0 (unless it's been subnetted up a bit).

 

Class A allows you to have a hell of a lot more than 250 hosts talking to each other than just your standard class C 255.255.255.0 mask with 254 hosts

 

The network ID is only using the first octet under class A so the remaining three octets are used for the host IDs.....so that's a hell of a lot of ip addresses........

 

Check to see what your subnet mask is.

[jmair]

Thanks for the help.

 

255.255.0.0 is our subnet.

 

So if I wanted the range of 10.1.1.1 to 10.1.254.254, my subnet should be 255.0.0.0 ?

[Joedetic]

As far as i understand it, if you've got a 10.0.0.0 class A network your subnet mask should be 255.0.0.0.

 

255.255.0.0 is for a class B network (172.something.0.0). But if you're 10.1 part of your IP address is staying the same i doubt this is going to have much effect. Try it though!

 

Can someone confirm that for me so i'm not ill-advising jmair there please?

[CyberNerd]

the class A network address has been subnetted using a 255.255.0.0 subnet mask, this gives a maximum of 65000 or so hosts. just because 10.1 is class A doesn't mean it can't be divided further. - I'm not so sure why jmair can't get more thatn 255 hosts with that range though

[Joedetic]

That's what i thought...and tried to say in a kind of obscure roundabout way without confusing people. If the 10.1 is staying the same as a subnetID then that should allow from 10.1.0.1 all the way to 10.1.255.254 with your /16 mask.

 

Odd...very odd.

[ajbritton]

The subnet mask of 255.255.0.0 means that the first two octets are the network address (so 10.1.2.3 means network is 10.1.0.0 and host address is 2.3).

 

As CyberNerd points out, it is perfectly valid to subnet a class A address.

 

If DHCP server is configured to give out 10.1.0.1 to 10.1.255.254 with subnet mask of 255.255.0.0, then it should work fine.

 

One thing to note is that the subnet mask must also be set correctly on all machines with static IPs (specifically, the DHCP server itself), or they will be unable to communicate with the clients.

[jmair]

Thanks for the help and clearificatioin. I'll play with this over the weekend. Maybe a good healthy power cycle is what it needs.

 

If I dont post back, that meens it works.

 

JMair

[ajbritton]

@JMair - If you have no luck, please can you restate the symptoms of the problem you are having (like what exactly is not working). I was not clear from the original post exactly what the problem was.

[Oops_my_bad]

Also I'm guessing you issue your own IP's and not your LEA?