client
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... hlen 1 Hardware address length
hops 1 Client sets to zero, optionally used by relay agents
when booting via a relay agent ...
... xid 4 Transaction ID, a random number chosen by the
client, used by the client and server to associate
messages and responses between a client ...
... Transaction ID, a random number chosen by the
client, used by the client and server to associate
messages and responses between a client and a
...
... by the
client, used by the client and server to associate
messages and responses between a client and a
server.
secs 2 Filled in by client ...
... server.
secs 2 Filled in by client, seconds elapsed since client
began address acquisition or renewal process.
...
... booting via a relay agent.
chaddr 16 Client hardware address. Should be unique.
sname 64 Optional server host name ...
... identifier unique to the virtual subnet.
The client MUST use the same chaddr field in all subsequent messages
within the same DHCPv4 exchange. In addition, the chaddr SHOULD be
...
... For use in DHCPv4 configuration of IPsec tunnel mode, the client-
identifier option MUST be included, MUST be unique within the virtual
...
...
Note that these filters will work not only for a client without
configuration, but also with a client that has previously obtained a
...
... filters will work not only for a client without
configuration, but also with a client that has previously obtained a
configuration lease, and is attempting to renew it. In the latter
case, the DHCP ...
... field. In this case, the security gateway relays packets between the
client and the DHCPv4 server, but does not request or renew addresses
...
... DHCPv4 server, but does not request or renew addresses
on the client's behalf. While acting as a DHCP Relay, the security
gateway MAY implement DHCP ...
...
To learn the internal IP address of the client in order to route
packets to it, the security gateway ...
... tunnel mode SA. All future DHCP messages sent by the client,
including DHCPREQUEST, DHCPINFORM ...
... Several mechanisms can be used to enable remote hosts to be assigned
different configurations. For example, clients may use the User
Class Option [16 ...
... DHCPv4 server may also take a number of other variables into account,
including the htype/chaddr; the host name option; the client-
identifier option; the DHCP Relay Agent ...
... 15].
Conditional configuration of clients, described in [18], can be used
to solve a number of problems, including assignment of options based
...
... 18], can be used
to solve a number of problems, including assignment of options based
on the client operating system; assignment of groups of clients ...
... ranges for remote hosts; assignment of
static routes to clients [20], etc. As noted in the security
considerations, these mechanisms, while useful, do not enhance
...
...
As described in [17], a number of issues arise when forwarding DHCP
client requests from untrusted sources. These include DHCP
exhaustion attacks ...
... spoofing of the client identifier option or
client MAC address. These issues can be partially addressed through
use of the DHCP ...
... authentication [5]. This is because the security
gateway will not typically have access to the client
credentials necessary to issue an DHCPv4 ...
... allocation of an IP address on their own behalf, and then assign this
to the client via IKECFG. Since IKECFG does not support the concept
of an address lease, the security gateway ...
... state, the
DHCPACK will be sent directly to the client, which will not be
expecting it. As a result, it is either necessary for the security
gateway to add special code to avoid forwarding such packets, or to
...