NAME

nemesis-dhcp — DHCP Protocol (The Nemesis Project)

SYNOPSIS

DESCRIPTION

nemesis is designed to be a command line-based, portable human IP stack for UNIX-like and Windows systems. The suite is broken down by protocol, and should allow for useful scripting of injected packets from simple shell scripts.

nemesis-dhcp provides an interface to craft and inject DHCP packets allowing the user to specify any portion of a DHCP packet as well as lower-level IP and TCP/UDP packet information.

By default a DHCP Discover (client) message is created. To successfully send it out a network interface you must be root.

GENERAL OPTIONS

-c COUNT

Number of packets to send, default: 1.

-i INTERVAL

Seconds between repeatedly sent packets, only available if -c is given.

-v

Display the injected packet in human readable form. Use twice to see a hexdump of the injected packet with printable ASCII characters on the right. Use three times for a hexdump without decoded ASCII.

DHCP OPTIONS

-o CODE

BOOTP/DHCP opcode to send, default: 1 (request).

-f FLAGS

Specify the FLAGS within the DHCP header, default: 0x8000.

-g ADDR

DHCP Gateway (relay agent) IP address.

-s ADDR

DHCP server IP address.

-C ADDR

DHCP client's IP address.

-Y ADDR

Your IP address, the lease from the DHCP server.

-h MAC

Client's HW address, MAC.

-P FILE

This will cause nemesis-dhcp to use the specified FILE as the payload when injecting DHCP packets. For packets injected using the raw interface (where -d is not used), the maximum payload size is 65455 for DHCP packets. For packets injected using the link layer interface (where -d IS used), the maximum payload size is 1420 bytes. Payloads can also be read from stdin by specifying -P- instead.

The payload file can consist of any arbitrary data though it will be most useful to create a payload resembling the structure of the DHCP packet specified using the command-line options.

NOTE: Windows systems are limited to a maximum payload size of 1420 bytes.

UDP OPTIONS

-x PORT

UDP source port of injected packet.

-y PORT

UDP target port of injected packet.

IP OPTIONS

-D ADDR

Specify the destination IP address in the IP header.

-F OPT

Specify the fragmentation options in the IP header:

-FD

don't fragment

-FM

more fragments

-FR

reserved flag

-F offset

 

IP fragmentation options can be specified individually or combined into a single argument to the -F command line switch by separating the options with commas (eg. -FD,M) or spaces (eg. -FM 223). The IP fragmentation offset is a 13-bit field with valid values from 0 to 8189. Don't fragment (DF), more fragments (MF) and the reserved flag (RESERVED or RB) are 1-bit fields.

NOTE: Under normal conditions, the reserved flag is unset.

-I ID

Specify the IP ID in the IP header.

-O FILE

This will cause nemesis-dhcp to use the specified IP options file, FILE, as the options when building the IP header for the injected packet. IP options can be up to 40 bytes in length. The IP options file must be created manually based upon the desired options. IP options can also be read from stdin by specifying -O- instead of an IP options file.

-S ADDR

Specify the source IP address in the IP header.

-t TOS

Specify the IP type-of-service (TOS) in the IP header. Valid type of service values:

2

Minimize monetary cost

4

Maximize reliability

8

Maximize throughput

24

Minimize delay

NOTE: Under normal conditions, only one type of service is set within a packet. To specify multiple types, specify the sum of the desired values as the type of service.

-T TTL

Specify the IP time-to-live (TTL) in the IP header.

DATA LINK OPTIONS

-d IFNAME

Specify the name (for UNIX-like systems) or the number (for Windows systems) of the IFNAME to use (eg. fxp0, eth0, hme0, 1).

-H MAC

Specify the source MAC address, (XX:XX:XX:XX:XX:XX).

-M MAC

Specify the destination MAC address, (XX:XX:XX:XX:XX:XX).

-Z

Lists the available network interfaces by number for use in link-layer injection.

NOTE: This feature is only relevant to Windows systems.

DIAGNOSTICS

nemesis-dhcp returns 0 on a successful exit, 1 if it exits on an error.

SEE ALSO

nemesis-arp(1), nemesis-dns(1), nemesis-ethernet(1), nemesis-icmp(1), nemesis-igmp(1), nemesis-ip(1), nemesis-ospf(1), nemesis-rip(1), nemesis-tcp(1), nemesis-udp(1).

AUTHORS

Joachim Nilsson <troglobit@gmail.com>

BUGS

Please report at https://github.com/libnet/nemesis/issues