Re: do we support non contiguous netmasks ?

From: Anders Lowinger (anders.lowinger_at_packetfront.com)
Date: 04/06/04

  • Next message: krishnan.n (shyam): "Re: Driver porting." 
    Date: Tue, 06 Apr 2004 14:24:09 +0200
To: Andre Oppermann <andre@freebsd.org>

    Andre Oppermann wrote:

    >> interface ethernet 0
    >> ip address 192.168.0.0 mask 255.255.253.0
    >
    > This is simply a supernet (aka classless) but *not* a non-contignous
    > netmask. A non-contignous netmask would look like 255.254.255.0.

    Nope, 255.255.253.0 binary is 11111111.11111111.11111101.00000000
    which is non-contignous.

    >> interface ethernet 0
    >> ip address 192.168.0.0 mask 255.255.255.0
    >> ip address 192.168.2.0 mask 255.255.255.0 secondary
    >>
    >>which gives the same functionality with contigious netmasks.
    >
    > Not really.

    Agree, not exactly the same

    > With the your second example hosts on the network have
    > to have different default gateways (192.168.0.1 and 192.168.2.1)
    > depending in which network range they are. In your first example
    > you just have one default gateway for all of them. However the
    > netmask has to match on all hosts otherwise you run into all sorts
    > of wierd trouble.

    In this case, the above is normally only used during a migration
    phase (as I mentioned, this is the only use of non-contignous i've
    seen, joining two separate subnets), so the hosts already have the
    correct default-route in their subnet. Hosts could optionally then
    be migrated to a common subnet.

    /Anders
    _______________________________________________
    freebsd-net@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-net
    To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"

  • Next message: krishnan.n (shyam): "Re: Driver porting."

    Relevant Pages