Cisco DHCP Relay Agent - strange thing..

Discussion in 'Cisco' started by bjoern.hoefer, Jan 20, 2006.

  1. Hello,

    I have worked the whole week to get our new-DHCP Schema working. - No
    it works, but i really don't know why...

    Catalyst 3550 12G Configuration (Backbone Switch)

    ip dhcp relay information trust-all

    Interface Vlan 1
    IP Adresses:
    ....(many other addresses)
    ip helper address

    Interface VLAN 610

    I want that our DHCP Server (Win2003) serves our Clients with
    10.10.6.x/24 IP Adresses. (and later 192.168.199.x/24, and other
    192.168.x.x/24 Scopes)

    The server has an interface in VLAN 610 and the DHCP-Server is bounded
    to that Interface.

    When I use the configuration above, it works fine (The clients get
    10.10.6.x/24 IPs and 192.168.199.x/24 IPs).
    But if I change the primary IP-Adress of VLAN 1 Interface to e.g., the clients get no lease.

    The leases reach the DHCP-Server, but it does'nt react on the
    DHCPDISCOVER (GIADDR ist the primary ip of the Switch).
    No DHCPOFFER, no log-file entry, the only chance to ensure, that the
    packets reach the server is to use a sniffer, like etheral.

    Is this a problem of the Windows 2003 Server or an logical mistake by

    Best greets

    Bjoern A. Hoefer
    bjoern.hoefer, Jan 20, 2006
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  2. bjoern.hoefer

    helpdesk Guest

    Hello Bjoern,

    how are your scopes defined ? I believe that with secondary addressing,
    you will need a single superscope with a scope inside for each subnet
    defined on your interface. So in your case that would mean a suoerscope
    with scopes for,, etc...

    We've got answers !
    helpdesk, Jan 20, 2006
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