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DHCP

mr@cipex.dk
Beginner
Beginner

Hi

 

I have a project where I use a ISR4331 as DHCP server. I need to assign same the same IP address to the same mac address at every connection. There is around 150 devices to be connected and therefore I'm trying to avoid making a BIG config file with 150 address pool - is there a simple way to do that?

My plan is to set lease time to 5 - 10 days...

 

But if a DHCP client has an address and we have a power failure / reload at the router - is the DHCP database then lost.

Does anybody know the behavior of the Cisco DHCP server in case od power failure?

Is there a simple way to assign IP address to one mac?

 

Thanks in advance,

Michael

4 Replies 4

paul driver
VIP Expert VIP Expert
VIP Expert

Hello

When a router reloads it loses its the binding table as this is stored is ram, However you can back it up off site and if/when the rtr reloads it then will restore the binding table as it was before the reload.

ip dhcp database tftp://1.1.1.1/dhcp

As for static clients you want to have 150 statics serviced from the rtr - correct?


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Hmmm, OK - Is there a way to make it easy here?

Hello

So you do want 150 static mappings?

Then you could then use a origin file in a single static dhcp pool and have another pool for dynamic allocation but you would need to exclude the static mapping from the dynamic pool.

 

Example:

ip dhcp database tftp://1.1.1.1/binding.txt  < to save the binding table after reload of rtr
ip dhcp excluded-address 192.168.1.100 192.168.1.249  <-to excluded the 150 static mappings

ip dhcp pool LAN <- dynamic dhcp client pool
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
dns-server 192.168.1.1
lease 0 8

ip dhcp pool static <- static dhcp client pool
origin file tftp://1.1.1.1/static.txt  < source of static file for client static binding
default-router 192.168.1.1
dns-server 192.168.1.1
lease 5

 

Origin file:
Ip address          Type           Hardware address
192.168.1.100     ID               0111.1111.1111


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Tank you all - I've just hoped that a solution like Cisco Meraki was available.

I've choosen to assign static adresses to the devices instead.

 

 

Best regards,

Michael

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