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DHCP on cisco router

vburshteyn asked
Medium Priority
Last Modified: 2012-05-11
hi folks,

I set up a DHCP on a router.

iip dhcp pool VOICE
   option 150 ip
   lease 5

No i need to set the lease for about 30 minutes.

is that
lease 0 0 30 ?

second how can i clear out the leases or have then refresh so the phones know that the lease is for only 30 minutes.

Watch Question

Top Expert 2011

Cisco's terminal is pretty good. Did you try putting in

lease ?

to see if it would spit out the parameters?


yes it gives me an option only for days, but we are in the process of pushing out a new phone system and i need the system to update faster.
Top Expert 2011
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Top Expert 2011

It looks like it would be

lease 0 0 30 like you stated before.
Don JohnstonInstructor
Top Expert 2015

IIRC, "clear ip dhcp binding" or "clear dhcp binding"
Hello Dear,

Troubleshooting commands from the CCNA Command Guide

router(config)#service dhcp
! Verifies that the router can use DHCP services and that DHCP is enabled

router#show ip dhcp binding
! Displays a list of all bindings created

Router#show ip dhcp binding w.x.y.z
! Displays the bindings for a specific DHCP client with an IP address of w.x.y.z

Router#clear ip dhcp binding a.b.c.d
! Clears an automatic address binding from the DHCP server database

Router#clear ip dhcp binding *
! Clears all automatic DHCP bindings

Router#show ip dhcp conflict Displays a list of all address conflicts
! recorded by the DHCP server

Router#clear ip dhcp conflict a.b.c.d
!Clears address conflict from the database

Router#clear ip dhcp conflict *
!Clears conflicts for all addresses

Router#show ip dhcp database
!Displays recent activity on the DHCP database

Router#show ip dhcp server statistics
!Displays a list of the number of messages sent and received by the DHCP server

Router#clear ip dhcp server statistics
!Resets all DHCP server counters to 0

Router#debug ip dhcp server {events | packets | linkage | class}
!Displays the DHCP process of addresses being leased and returned
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