how to add more than 254 ip address

[rizduan7]

hello everyone!

i have one Forti Gate 60E

i have configured the Forti Gate to use this range Dhcp 192.168.1.50-192.168.1.240 

my sub net mask 255.255.255.0 

but it seems like i need more IP address, can someone help me to increase available IP address?

[FortiUser5]

Hello Pavan,

Building A

Building B

Building B is a subnet of Building A.

So, if I have understood what you said, to increase my IP addresses in Building B, I have to change the following:

Building B

10.1.20.1 -----> 10.1.19.1

255.255.255.0 -----> 255.255.254.0

Address Range

10.1.20.51-10.1.20.250 -----> 10.1.19.51-10.1.20.250

I am learning as I go and before changing something, I would like to have a confirmation that what I am about to do will not create any issue.

Thank you in advance.

[AndyNZ]

Hi rizduan7,

Why do you think you need more IP addresses?

Are you:-

- experiencing issues where devices are unable to get an IP address after a period of time?

If this is the case your DHCP pool is likely exhausted because of long DHCP lease times. To resolve this reduce the DHCP lease time from the default value of 604800 (7 days) to something sensible (7200 is usually fine).

- expecting more than 254 devices at the same time?

If this is the case then increase the IP address range as others replying have suggested. However the 60E is a modest box- it technically isn't expected to support that many clients.....

Kind Regards,

[Gaganjgoyal]

Thank you. I need to know more like my current setting is as pasted below, but all the IP being exhausted due to big network. I wanted to create more range like 192.168.2.1 and so on. Can you please confirm what should I put in IP/Network Mask and what to put in DHCP server under IP Range...

[Toshi_Esumi]

I would suggest you expand the subnet from /24 to /23, which would double the range to 512, without needing to change the interface/GW IP.
Like 192.168.0.0/23 or /255.255.254.0, which include both 192.168.0.0/24 and 192.168.1.0/24. Then DHCP server range can be like 192.168.0.1 - 192.168.0.255 (or 192.168.1.0) and 192.168.1.2 - 192.168.1.254. You can keep the interfaced IP but change the mask: 192.168.1.1/255.255.254.0.

Toshi