How To Increase Dhcp Scope

If you lot run out of available IP addresses on a Windows Server DHCP scope devices on the LAN will fail to obtain an IP address and volition not be able to connect to the network.

A brusk-term fix for this is to decrease the DHCP lease time. It by and large starts at eight hours and tin can be reduced to recycle IP addresses back into the lease pool.

A long-term fix for this is to increase the size of the DHCP scope. This will increment the number of available IP addresses.

A typical DHCP telescopic will take the following:

An address pool, which specifies what IP addresses are available to exist handed out. The address pool is typically like this:
- 192.168.0.one through 192.168.0.254 or
- 192.168.i.i through 192.168.one.254 or
- x.0.0.i through 10.0.3.254
A exclusion list, which marks ane or more IP addreses in the range as unavailable to exist handed out. This is useful if you take devices - printers and the like - that have a static IP address fix which cannot be handed out to whatsoever other device
1 or more DHCP reservations, which ensure a DHCP device on the network always has the aforementioned IP address
A subnet mask, which tells a device whether to send network traffic to a peer on the same network or to send it via the router
The router IP address
The DNS server(south) IP address(es) for resolving domain names to IP addresses

The simplest style to expand the telescopic is to delete it and create a new one to supercede it with a larger range of bachelor IP addresses. This is the best solution if you lot don't take a large number of reservations and customisations on the DHCP scope. If you practice have a large number of DHCP customisations it'southward ameliorate to export the DHCP scope, amend information technology externally, and so delete the scope on the server and re-import the amended scope. Here'south how to to it:

Take a backup of the DHCP telescopic. Open control prompt as Administrator and practice the following:
netsh dhcp server \\"Server name" scope " scope subnet " dump>c\:dhcp.txt
i.east.
netsh dhcp server \\Server-DC01 scope 10.0.0.0 dump > c:\dhcp.txt
Open the c:zdhcp.txt file with a text editor and change the IP range AND THE SUBNET MASK
192.168.0.1 to 192.168.0.254 will have a subnet mask of 255.255.255.0 with 254 available addresses
192.168.0.1 to 192.168.3.254 will take a subnet mask of 255.255.252.0 with 1,000 available addresses. This is what the exported scop will wait similar:
Dhcp Server \\SRV01.ACMECORP.local add telescopic 192.168.0.0 255.255.255.0 "SteinerScope" ""
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 ready state i
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 set delayoffer 0

# ======================================================================
# First Add Ipranges to the Scope 192.168.0.0, Server SRV01.ACMECORP.local
# ======================================================================

Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Add together iprange 192.168.0.1 192.168.0.254
Dhcp Server \\SRV01.ACMECORP.local scope 192.168.0.0 set napstate Off

# ======================================================================
# End Add Ipranges to the Scope 192.168.0.0, Server SRV01.ACMECORP.local
# ======================================================================

# ======================================================================
# Start Add together Excluderanges to the Telescopic : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 add excluderange 192.168.0.52 192.168.0.52
Dhcp Server \\SRV01.ACMECORP.local Telescopic 192.168.0.0 add excluderange 192.168.0.63 192.168.0.63
Dhcp Server \\SRV01.ACMECORP.local Telescopic 192.168.0.0 add together excluderange 192.168.0.i 192.168.0.29
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 add excluderange 192.168.0.44 192.168.0.44
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 add excluderange 192.168.0.200 192.168.0.254

# ======================================================================
# Stop Add Excluderanges to the Telescopic : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

# ======================================================================
# Start Add OptionValues to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 fix optionvalue 51 DWORD "7200"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 set optionvalue 3 IPADDRESS "192.168.0.1"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 set optionvalue 15 STRING "ACMECORP.local"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 set optionvalue six IPADDRESS "192.168.0.254"

# ======================================================================
# Cease Add OptionValues to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

# ======================================================================
# Commencement Add ReservedIp to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Add reservedip 192.168.0.45 fc15b4336f52 "NPI336F52.ACMECORP.local" "Main Part Printer P3015" "BOTH"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Add reservedip 192.168.0.68 c4346b1736e8 "NPI1736E8.ACMECORP.local" "" "DHCP"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Add reservedip 192.168.0.149 b083febe1cd6 "DESKTOP-3MEJ7J3.ACMECORP.local" "Neil Tancock Desktop - DNS unfiltered" "DHCP"

Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 set up reservedoptionvalue 192.168.0.43 6 IPADDRESS "8.8.viii.viii" "8.viii.4.4"
Dhcp Server \\SRV01.ACMECORP.local v4 Scope 192.168.0.0 Set NameProtection enable= 0
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Set up DnsConfig i 0 1 0

# ======================================================================
# End Add together ReservedIp to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================
The new scope with take the IP address range and subnet mask inverse. The changes are marked in green:
Dhcp Server \\SRV01.ACMECORP.local add scope 192.168.0.0 255.255.252.0 "SteinerScope" ""
Dhcp Server \\SRV01.ACMECORP.local Telescopic 192.168.0.0 fix land i
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 fix delayoffer 0
# ======================================================================
# Start Add Ipranges to the Scope 192.168.0.0, Server SRV01.ACMECORP.local
# ======================================================================

Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Add iprange 192.168.0.1 192.168.3.254
Dhcp Server \\SRV01.ACMECORP.local scope 192.168.0.0 fix napstate Off

# ======================================================================
# Terminate Add Ipranges to the Scope 192.168.0.0, Server SRV01.ACMECORP.local
# ======================================================================

# ======================================================================
# First Add Excluderanges to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

Dhcp Server \\SRV01.ACMECORP.local Telescopic 192.168.0.0 add together excluderange 192.168.0.52 192.168.0.52
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 add together excluderange 192.168.0.63 192.168.0.63
Dhcp Server \\SRV01.ACMECORP.local Telescopic 192.168.0.0 add excluderange 192.168.0.one 192.168.0.29
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 add excluderange 192.168.0.44 192.168.0.44
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 add excluderange 192.168.0.200 192.168.0.254

# ======================================================================
# End Add Excluderanges to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

# ======================================================================
# Showtime Add OptionValues to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 gear up optionvalue 51 DWORD "7200"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 set optionvalue 3 IPADDRESS "192.168.0.i"
Dhcp Server \\SRV01.ACMECORP.local Telescopic 192.168.0.0 set optionvalue xv STRING "ACMECORP.local"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 fix optionvalue 6 IPADDRESS "192.168.0.254"

# ======================================================================
# Stop Add OptionValues to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

# ======================================================================
# Start Add ReservedIp to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================

Dhcp Server \\SRV01.ACMECORP.local Telescopic 192.168.0.0 Add reservedip 192.168.0.45 fc15b4336f52 "NPI336F52.ACMECORP.local" "Main Office Printer P3015" "BOTH"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Add reservedip 192.168.0.68 c4346b1736e8 "NPI1736E8.ACMECORP.local" "" "DHCP"
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Add together reservedip 192.168.0.149 b083febe1cd6 "DESKTOP-3MEJ7J3.ACMECORP.local" "Neil Tancock Desktop - DNS unfiltered" "DHCP"

Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 ready reservedoptionvalue 192.168.0.43 6 IPADDRESS "viii.8.8.8" "viii.8.4.4"
Dhcp Server \\SRV01.ACMECORP.local v4 Scope 192.168.0.0 Set up NameProtection enable= 0
Dhcp Server \\SRV01.ACMECORP.local Scope 192.168.0.0 Prepare DnsConfig 1 0 one 0

# ======================================================================
# End Add ReservedIp to the Scope : 192.168.0.0, Server : SRV01.ACMECORP.local
# ======================================================================
Save the modified c:\dhcp.txt file as c:\newdhcp.txt
Go dorsum to the DHCP server and delete the telescopic completely
Then go dorsum to the Ambassador command prompt and enter the following command:
netsh exec c:\newdhcp.txt

This will import the DHCP telescopic with all your settings intact and will also increase the bachelor
IP addresses and, critically, volition change the subnet mask.  Y'all may need to restart the DHCP server
for the changes to take consequence.