nemesis-tcp(1) (usm)
nemesis-tcp(1) General Commands Manual (usm) nemesis-tcp(1)

NAME

nemesis-tcpTCP Protocol (The Nemesis Project)

SYNOPSIS

nemesis-tcp [-vZ?] [-a NUM] [-c COUNT] [-d IFNAME] [-D ADDR] [-f -AR -FLAG] [-F OPT] [-I ID] [-i INTERVAL] [-M MAC] [-o FILE] [-O FILE] [-P FILE] [-s NUM] [-S ADDR] [-t TOS] [-T TTL] [-u OFFSET] [-w SIZE] [-x PORT] [-y PORT]

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

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.

TCP Options

-a NUM
Specify the acknowledgement number (ACK number) within the TCP header.
-F FLAG
Specify the TCP flags within the TCP header. The following flags are supported:
-fS
SYN
-fA
ACK
-fR
RST
-fP
PSH
-fF
FIN
-fU
URG
-fE
ECE
-fC
CWR
-f-
NONE
Flags can be combined in the form ‘-fPA’. If flags are specified in the form ‘-f-’ then the TCP header will be built without flags.
-o FILE
This will cause nemesis-tcp to use the specified TCP options file as the options when building the TCP header for the injected packet. TCP options can be up to 40 bytes in length. The TCP options file must be created manually based upon the desired options. TCP options can also be read from stdin by specifying ‘-o-’ instead.
-P FILE
This will cause nemesis-tcp to use the specified payload file as the payload when injecting TCP packets. For packets injected using the raw interface (where -d is not used), the maximum payload size is 65415 bytes. For packets injected using the link layer interface (where -d IS used), the maximum payload size is 1380 bytes. Payloads can also be read from stdin by specifying ‘-P-’ instead.
Windows systems are limited to a maximum payload size of 1380 bytes for TCP packets.
-s NUM
Specify the sequence number within the TCP header.
-u OFFSET
Specify the urgent pointer offset within the TCP header.
-w SIZE
Specify the window size within the TCP header.
-x PORT
Specify the source port within the TCP header.
-y PORT
Specify the destintion port within the TCP header.

IP OPTIONS

-D ADDR
Specify the destination IP address within 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 within the IP header.
-O FILE
This will cause nemesis-tcp to use the specified IP options 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.
-S ADDR
Specify the source IP address within the IP header.
-t TOS
Specify the IP type of service (TOS) within 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-tcp returns 0 on a successful exit, 1 if it exits on an error.

SEE ALSO

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

AUTHORS

Mark Grimes <mark@stateful.net> and
Jeff Nathan <jeff@snort.org>

BUGS

Please report at https://github.com/troglobit/nemesis/issues
December 16, 2019