Increasing DHCP Address pool Scope

[MattDLEA]

I need to add more IP Addresses to our scope at the moment the start ip is 10.73.3.20 and the end is 10.73.3.100 if i changed the end to 10.73.3.150 would anything bad happen?

[localzuk]

So long as your netmask matches the subnet, there shouldn't be any issues.

[MattDLEA]

subnet mask is 255.255.240.0 ?

[localzuk]

That's larger than the scope, so I can't imagine it causing any issues.

[clareq]

Just make sure you have no devices with static IPs (such as printers) in the range you are extending to.

[MattDLEA]

There was a expresso box with a ip in that range so i just added that ip as an exclusion?

[clareq]

That will work.

[smithson83]

Is it a range given to you by the LEA, if so, you may need to check that it doesnt conflict with another school.

 

When we ran out of IP's we have to get a completely different range from the LEA so we could expand over multiple class C's

[MattDLEA]

Just changed it.. Seams ok .

 

Just phoned the grid to see if they say its ok lol

 

Probably done it the wrong way round

[smithson83]

Just changed it.. Seams ok .

 

Just phoned the grid to see if they say its ok lol

 

Probably done it the wrong way round

 

easier to ask for forgiveness than to seek permission

[smithson83]

Someone correct me if im wrong

 

a NW of 10.73.3.20:255.255.240.0 would span 10.73.0.0-10.73.15.0. This being the case, either you have around 4000 free IP's available, or there are other schools on the same ClassC address?

 

Either way, i think this needs more thinking about and more info from the LEA

[MattDLEA]

Just found out that our photocopiers are 10.73.15.251 ?!?!

[smithson83]

Sounds like your already using the full range then (albeit unknowingly).

 

But it still seems a tad much for s single school, 4096 IP's is a lot which ever way you look at it, which leads me to believe it may be shared amongst other schools.

 

Which poses another question as to why the Subnet is .240, I would of though it would be .255 or .254, ours was increased to .252 giving us 1022 IP's which is a bit overkill, but I didnt complain.

Edited November 19, 2013 by smithson83

[Mr_Jiminy]

It all depends what statics are assigned above 100 (shutting the stable door after the horse has bolted).

It may be the LA haven't got any devices on statics above the assigned scope, but I would have certainly checked prior to extending... Not everyone will assign a reservation

Also, definitely worth keeping a record of the number of network devices you have, both on statics and obtaining leases... Don't forget WAP's

[localzuk]

Sounds like your already using the full range then (albeit unknowingly).

 

But it still seems a tad much for s single school, 4096 IP's is a lot which ever way you look at it, which leads me to believe it may be shared amongst other schools.

 

Which poses another question as to why the Subnet is .240, I would of though it would be .255 or .254, ours was increased to .252 giving us 1022 IP's which is a bit overkill, but I didnt complain.

 

It all depends how you subnet your network. We have a .240 here now, as a .252 was not enough in a subnetted environment for our needs. When you've got a need for 4 different wireless vlans (guest, byod, 802.11X, hidden 'admin'), along with subnets for suites, phone VLAN, management VLAN, thin clients etc... You soon chop it up and those 4096 aren't 4096 any more.