network
Click on the red underlined text to get to the source
...
The time required to detect movement between networks and to obtain
(or to continue to use) an operable IPv4 configuration may be
...
... RFC2131], and IPv4 Link-Local
addresses [RFC3927], a set of steps known as Detecting Network
Attachment for IPv4 (DNAv4). DNAv4 optimizes the (common) case of
...
... DNAv4). DNAv4 optimizes the (common) case of
re-attachment to a network that one has been connected to previously
by attempting to re-use a previous (but still valid) configuration,
...
... state. If an address previously
obtained on the new network is still operable, DNAv4 enables the host
...
... ARP has a number of benefits. One benefit is that
unicast packets impose less burden on the network than broadcast
packets, particularly on 802.11 networks ...
... network than broadcast
packets, particularly on 802.11 networks where broadcast packets may
be sent at rates as low as 1 Mb/sec. Another benefit is that if the
...
... INIT-REBOOT), as well as to reduce multi-
second conflict detection delays when a host changes networks.
o As a performance ...
... DNAv4, just
without the performance benefit. Users and network operators
who desire the performance improvement offered by DNAv4 ...
... procedure.
For each network that it connects to, it is assumed that the host
saves the following parameters to stable storage:
...
... address, and lease expiration time.
From the set of networks that have operable IPv4 addresses associated
with them, the host ...
... with them, the host selects a subset and attempts to confirm the
configuration for each network, using the reachability test described
in Section 2.1.
...
... address
conflict. The reachability test is only carried out for a network
when the host has previously completed conflict detection as
...
... RFC2131] and
obtained an operable IPv4 configuration on that network.
Restrictions on sending ARP Requests and Responses are described in
...
... The host skips the reachability test for a network if any of the
following conditions are true:
...
... host does not have an operable routable IPv4 address on that
network. In this case, the reachability test cannot confirm that
the host ...
... addresses of any test nodes on that
network. In this case, insufficient information is available to
carry out the reachability test.
...
... use the operable routable IPv4 address associated with the confirmed
network, without needing to re-acquire it. Once a valid reachability
...
... reachability test does not return an answer, this is
typically because the host is not attached to the network whose
configuration is being tested. In such circumstances, there is
typically little value in aggressively retransmitting reachability ...
... address conflict is greatest when the host moves
between private networks, since in this case the completion of
conflict detection on the former network does not provide assurance
...
... between private networks, since in this case the completion of
conflict detection on the former network does not provide assurance
against an address ...
...
against an address conflict on the new network. Until a host has
confirmed the operability of its IPv4 configuration ...
... candidate configuration has been confirmed. Also, where a host moves
from one private network to another, an ICMP Echo Request can result
...
... IPv4 address remains the same. This can occur, for
example, where a host moves from one home network using prefix
192.168/16 to another one. In addition, if the ping ...
... host has an operable routable IPv4 address on one or more
networks, and if DHCPv4 is enabled on the interface, the host ...
... host does not have an operable routable IPv4 address on any
network, the host enters the INIT state ...
... receive a response regardless of whether the previously configured
IPv4 address is correct for the network to which it has connected.
Sending a DHCPREQUEST ...
... host does not have an operable routable IPv4 address on any
network, the host MAY configure an IPv4 Link-Local address ...
... RFC2131]. Where
a host can confirm that it remains connected to a network on which it
possesses an operable routable IPv4 address, that address ...
... host has an operable routable IPv4 address on one or more
networks but the reachability test cannot confirm the configuration
and the DHCPv4 client ...
... RFC2131] states that the client MAY choose to use the previously
allocated network address and configuration parameters for the
...
...
Typically, an address is manually assigned on a network because a
dynamically assigned address was not suitable for some reason.
...
... traffic is not secured, so an attacker gaining access to
the network can spoof a response to the reachability test described
in Section 2.1, leading the querier ...
... in Section 2.1, leading the querier to conclude falsely that it is
attached to a network that it is not connected to.
Similarly, where DHCPv4 ...
... DHCPv4 server, in order to convince the host that it
was attached to a particular network. This and other threats
relating to DHCPv4 ...
... host that disables its personal firewall based on
evidence that it had attached to a home network could be compromised
by spoofing of the DNAv4 ...
... Plummer, D., "Ethernet Address Resolution Protocol: Or converting network protocol addresses to 48.bit Ethernet address ...
... James Carlson
Sun Microsystems, Inc
1 Network Drive
Burlington, MA 01803-2757
USA
...