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Need to calculate range for a VLAN

nabeelkhan8086
Level 1
Level 1

We have  the following IP's assigned to the VLAN interfaces

 

interface Vlan100
ip address 172.30.168.2 255.255.255.0

(Range will be 172.30.168.0 - 172.30.168.255)


interface Vlan200
ip address 172.30.169.2 255.255.255.128

(Range will be 172.30.169.0 - 172.30.169.127)


interface Vlan300
ip address 172.30.170.2 255.255.254.0
(Unable to calculate the range for this VLAN)

 

Could some one please explain me how would I calculate the range of VLAN300 in detail as I am just a beginner.

4 Replies 4

luis_cordova
VIP Alumni
VIP Alumni

Hi @nabeelkhan8086 

 

172.30.170.0 - 172.30.171.255

 

172.30.1010 110|0.0000 0000= 172.30.170.0/23

172.30.1010 110|1.1111 1111= 172.30.171.255/23

 

Regards

rais
Level 7
Level 7

 172.30.170.2 255.255.254.0 = 172.30.170.2/23

In binary 170 = 1010 1010

The mask [255.255.254.0] makes the last bit of 170 to be don't care/Host bit, so it could be 1010 1010 or 1010 1011. 1010 1011 = 171

The range of IPs for this vlan is 172.30.170.1 to 172.30.171.254.

HTH

Jaderson Pessoa
VIP Alumni
VIP Alumni

Hello

 

 

interface Vlan100
ip address 172.30.168.2 255.255.255.0

(Range will be 172.30.168.0 - 172.30.168.255)


interface Vlan200
ip address 172.30.169.2 255.255.255.128

(Range will be 172.30.169.0 - 172.30.169.127)


interface Vlan300
ip address 172.30.170.2 255.255.254.0
(Unable to calculate the range for this VLAN)

(range will be ip address 172.30.170.0 - 172.30.171.255 )

 

11111111.11111111.11111110.00000000

in this case you have used one bit to get more hosts and to know how many hosts you will have, look exemple below;

11111111.11111111.1111111 0.        0         0       0       0       0     0      0      0

                                                        128       64      32      16     8     4      2      1  = 256

                                                512

if your fourth octect have 256 address available and you get more one, you will have + 256 host... in totally 512 address.

 

your network address will be: 172.30.170.0 255.255.254.0

 

 

 

 

Jaderson Pessoa
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vsurresh
Level 1
Level 1
The range would be 172.30.170.0 - 172.30.171.255
Network - 172.30.170.0
Broadcast - 172.30.171.255
Usable IPs - 510
subnet mask - /23

Refer to this link on how to calculate the subnet https://community.infosecinstitute.com/discussion/67245/quick-subnetting-all-in-your-head

Please let me know if you require any further help.

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Regards
Suresh
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