Multiple DHCP Servers - Netware

This is a discussion on Multiple DHCP Servers - Netware ; I am running NW6 SP5 on mulitple servers. I want to set up additional DHCP servers as standbys should the main one fail. I have set up the DHCP server, the subnet & the address range to be different from ...

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Thread: Multiple DHCP Servers

  1. Multiple DHCP Servers

    I am running NW6 SP5 on mulitple servers.

    I want to set up additional DHCP servers as standbys should the main one
    fail.

    I have set up the DHCP server, the subnet & the address range to be
    different from the primary servers. I use the RFC1918 172.16.x.x. class
    B range. I have a DHCP server issuing addresses in the 172.16.1.0 subnet
    & I have set up another server to dispense addresses in the 172.16.4.0
    subnet. The server base IP address is not in this range.

    The server starts up fine but won't allocate any addresses. Running
    DHCPSRVR with the -d3 switch shows that it says "received packet from
    172.16.0.0 subnet. Server is not configured to allocate addresses in
    this range".

    I saw in an old(ish) TID that the server base IP address had to be
    within the DHCP address range. Is this still true & is this why it's
    refusing to allocate addresses?
    Keith Bailey
    Computer Manager
    Kingsbury High School
    LONDON UK

  2. Re: Multiple DHCP Servers

    Keith Bailey wrote in
    news:1QuSeSAavdQBFwIQ@keefb.demon.co.uk:

    > I have set up the DHCP server, the subnet & the address range to be
    > different from the primary servers. I use the RFC1918 172.16.x.x. class
    > B range. I have a DHCP server issuing addresses in the 172.16.1.0 subnet
    > & I have set up another server to dispense addresses in the 172.16.4.0
    > subnet. The server base IP address is not in this range.
    >
    > The server starts up fine but won't allocate any addresses. Running
    > DHCPSRVR with the -d3 switch shows that it says "received packet from
    > 172.16.0.0 subnet. Server is not configured to allocate addresses in
    > this range".
    >
    > I saw in an old(ish) TID that the server base IP address had to be
    > within the DHCP address range. Is this still true & is this why it's
    > refusing to allocate addresses?


    What subnet mask do you use?
    If you use the class B subnet mask (255.255.0.0), it should work. If you
    use 255.255.255.0, you must be having a router between the 172.16.1.0 net
    and the 172.16.4.0 net. This router can most likely be configured to
    forward DHCP requests to the DHCP server.

    Remember the difference between subnets and subnet address ranges. You have
    a subnet, and within this subnet you have an address range. For example,
    you can reserve addresses 172.16.1.0-172.16.1.10 for routers, servers etc.,
    and let the DCHP server hand out addresses 172.16.1.11-172.16.1.254 to
    clients.

    For redundance, you have two choices:
    1. Have one server running, and another server configured, ready for a
    manual switch.

    2. Configure and run two DHCP servers. This is OK, as long as they don't
    hand out from the same address range.

    HTH,
    Erik Klausen

  3. Re: Multiple DHCP Servers

    On Fri, 10 Sep 2004 18:37:41 +0000, Erik Klausen wrote:

    > Keith Bailey wrote in
    > news:1QuSeSAavdQBFwIQ@keefb.demon.co.uk:
    >
    >> I have set up the DHCP server, the subnet & the address range to be
    >> different from the primary servers. I use the RFC1918 172.16.x.x. class
    >> B range. I have a DHCP server issuing addresses in the 172.16.1.0 subnet
    >> & I have set up another server to dispense addresses in the 172.16.4.0
    >> subnet. The server base IP address is not in this range.
    >>
    >> The server starts up fine but won't allocate any addresses. Running
    >> DHCPSRVR with the -d3 switch shows that it says "received packet from
    >> 172.16.0.0 subnet. Server is not configured to allocate addresses in
    >> this range".
    >>
    >> I saw in an old(ish) TID that the server base IP address had to be
    >> within the DHCP address range. Is this still true & is this why it's
    >> refusing to allocate addresses?

    >
    > What subnet mask do you use?
    > If you use the class B subnet mask (255.255.0.0), it should work. If you
    > use 255.255.255.0, you must be having a router between the 172.16.1.0 net
    > and the 172.16.4.0 net. This router can most likely be configured to
    > forward DHCP requests to the DHCP server.
    >
    > Remember the difference between subnets and subnet address ranges. You have
    > a subnet, and within this subnet you have an address range. For example,
    > you can reserve addresses 172.16.1.0-172.16.1.10 for routers, servers etc.,
    > and let the DCHP server hand out addresses 172.16.1.11-172.16.1.254 to
    > clients.
    >
    > For redundance, you have two choices:
    > 1. Have one server running, and another server configured, ready for a
    > manual switch.
    >
    > 2. Configure and run two DHCP servers. This is OK, as long as they don't
    > hand out from the same address range.
    >
    > HTH,
    > Erik Klausen


    Sounds like a job for Cluster Services (if you use it). Just add
    the dhcpsrvr as a cluster resource and forget about it.

    Cheers

    Alex
    Netware Geek
    Leeds Met University

  4. Re: Multiple DHCP Servers

    Erik,

    Thanks for the reply. I use 255.255.248 as the subnet mask & I am using,
    in effect, a class C address range (254 addreses). The range is within
    the server subnet mask but the server's IP address is outside the range
    that I want the DHCP server to dispense.


    In article , Erik Klausen
    writes
    >Keith Bailey wrote in
    >news:1QuSeSAavdQBFwIQ@keefb.demon.co.uk:
    >
    >> I have set up the DHCP server, the subnet & the address range to be
    >> different from the primary servers. I use the RFC1918 172.16.x.x. class
    >> B range. I have a DHCP server issuing addresses in the 172.16.1.0 subnet
    >> & I have set up another server to dispense addresses in the 172.16.4.0
    >> subnet. The server base IP address is not in this range.
    >>
    >> The server starts up fine but won't allocate any addresses. Running
    >> DHCPSRVR with the -d3 switch shows that it says "received packet from
    >> 172.16.0.0 subnet. Server is not configured to allocate addresses in
    >> this range".
    >>
    >> I saw in an old(ish) TID that the server base IP address had to be
    >> within the DHCP address range. Is this still true & is this why it's
    >> refusing to allocate addresses?

    >
    >What subnet mask do you use?
    >If you use the class B subnet mask (255.255.0.0), it should work. If you
    >use 255.255.255.0, you must be having a router between the 172.16.1.0 net
    >and the 172.16.4.0 net. This router can most likely be configured to
    >forward DHCP requests to the DHCP server.
    >
    >Remember the difference between subnets and subnet address ranges. You have
    >a subnet, and within this subnet you have an address range. For example,
    >you can reserve addresses 172.16.1.0-172.16.1.10 for routers, servers etc.,
    >and let the DCHP server hand out addresses 172.16.1.11-172.16.1.254 to
    >clients.
    >
    >For redundance, you have two choices:
    >1. Have one server running, and another server configured, ready for a
    >manual switch.
    >
    >2. Configure and run two DHCP servers. This is OK, as long as they don't
    >hand out from the same address range.
    >
    >HTH,
    >Erik Klausen


    Keith Bailey
    Computer Manager
    Kingsbury High School
    LONDON UK

  5. Re: Multiple DHCP Servers

    Keith Bailey wrote in
    news:ZfjpNpArNCRBFw1T@keefb.demon.co.uk:

    > Erik,
    >
    > Thanks for the reply. I use 255.255.248 as the subnet mask & I am
    > using, in effect, a class C address range (254 addreses). The range is
    > within the server subnet mask but the server's IP address is outside
    > the range that I want the DHCP server to dispense.


    It shouldn't be a problem. I use a 255.255.128.0-subnet mask, my DHCP-
    server's address is in the 10.16.32.0-range, and it hands out addresses in
    10.16.110.0-range.

    In DHCP, I assume you have created a subnet, and within this subnet you
    have a subnet address range? The subnet address range is the pool of
    addresses that the server hands out. Also, the DHCP server should be
    assigned to the subnet.

    If te DHCP environment is configured, check that the MAC address of the
    computer being rejected, isn't already in the DHCP database. If it is,
    delete it.
    This shouldn't be a problem, but then again, this is computer business :-)

    Erik Klausen

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