DHCP on cisco router

Posted on 2011-04-20
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.

Question by:vburshteyn
    LVL 13

    Expert Comment

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

    lease ?

    to see if it would spit out the parameters?

    Author Comment

    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.
    LVL 13

    Accepted Solution

    LVL 13

    Expert Comment

    It looks like it would be

    lease 0 0 30 like you stated before.
    LVL 50

    Expert Comment

    by:Don Johnston
    IIRC, "clear ip dhcp binding" or "clear dhcp binding"
    LVL 6

    Expert Comment

    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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