The Dynamic Host Configuration Protocol (DHCP) Request Packet
Validation exit program provides additional control for restricting which
incoming DHCP, DHCPv6 or
Bootstrap Protocol (BOOTP)
message request packets from client hosts are processed by the DHCP server, and
which should be rejected. Any restrictions that are imposed by the exit program are in
addition to any validation that is performed by the DHCP server program
through its configuration options. When an exit program is added to the
exit point, it is called by the DHCP server each time an incoming
DHCP, DHCPv6 or BOOTP request
packet is received,
but before any processing of the packet has taken place. The packet data is passed to
the exit program just as it was received off the network without any additional formatting or data
conversion. The exit program sets the allow operation parameter to
indicate whether the DHCP server should continue with normal processing of
the request packet. If the exit program indicates that the request packet
should be rejected, the DHCP server will discard the packet without any
further processing.
Note: Since this is an exit point of the DHCP server,
the exit program can only be used to restrict BOOTP packets if the DHCP
server is running. It cannot be used to restrict BOOTP packets from being
processed by the BOOTP server.
Authorities and Locks
None.
Required Parameter Group
Request packet
INPUT; CHAR(*)
The DHCP, DHCPv6 or BOOTP
message request packet that was initiated from some
client host and received by the DHCP server. It is in its initial form,
which is how it comes off of the network.
The formats of the packets are defined and maintained by the Internet
Engineering Task Force (IETF) standards body. See the following IETF
Request For Comments (RFC) documents for the specifications:
RFC 951, Bootstrap Protocol (BOOTP)
RFC 1542, Clarifications and Extensions for the Bootstrap
Protocol
RFC 2131, Dynamic Host Configuration Protocol
RFC 2132, DHCP Options and BOOTP Vendor Extensions
RFC 3315,
Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
Note: Since the packet is presented to the exit
program just as it was received from the network, it should be noted that
any data areas of the packet that are defined as type string or character
by the RFCs will be US-ASCII. On a System i® platform, it is recommended that this
data be treated as CCSID 819.
Length of request packet
INPUT; BINARY(4)
The length (in bytes) of the request packet.
Allow operation
OUTPUT; BINARY(4)
Whether the DHCP server should continue processing the request packet,
or whether it should be rejected. The possible values are:
0
The request packet should be rejected
1
Processing of the request packet should be allowed to
continue
DHCP, DHCPv6 or
Bootstrap Protocol (BOOTP)
message request packets from client hosts are processed by the DHCP server, and
which should be rejected. Any restrictions that are imposed by the exit program are in
addition to any validation that is performed by the DHCP server program
through its configuration options. When an exit program is added to the
exit point, it is called by the DHCP server each time an incoming