tcpbridge(1) User Commands tcpbridge(1)NAMEtcpbridge - Bridge network traffic across two interfaces
SYNOPSIStcpbridge [-flags] [-flag [value]] [--option-name[[=| ]value]]
All arguments must be options.
tcpbridge is a tool for selectively briding network traffic across two
interfaces and optionally modifying the packets in between
DESCRIPTION
The basic operation of tcpbridge is to be a network bridge between two
subnets. All packets received on one interface are sent via the other.
Optionally, packets can be edited in a variety of ways according to
your needs.
For more details, please see the Tcpreplay Manual at: http://tcpre‐
play.appneta.com
OPTIONS-r string, --portmap=string
Rewrite TCP/UDP ports. This option may appear up to 9999 times.
Specify a list of comma delimited port mappingings consisting of
colon delimited port number pairs. Each colon delimited port
pair consists of the port to match followed by the port number
to rewrite.
Examples:
--portmap=80:8000 --portmap=8080:80 # 80->8000 and 8080->80
--portmap=8000,8080,88888:80 # 3 different ports become 80
--portmap=8000-8999:80 # ports 8000 to 8999 become 80
-s number, --seed=number
Randomize src/dst IPv4/v6 addresses w/ given seed. This option
may appear up to 1 times. This option must not appear in combi‐
nation with any of the following options: fuzz-seed. This
option takes an integer number as its argument.
Causes the source and destination IPv4/v6 addresses to be pseudo
randomized but still maintain client/server relationships.
Since the randomization is deterministic based on the seed, you
can reuse the same seed value to recreate the traffic.
-N string, --pnat=string
Rewrite IPv4/v6 addresses using pseudo-NAT. This option may
appear up to 2 times. This option must not appear in combina‐
tion with any of the following options: srcipmap.
Takes a comma delimited series of colon delimited CIDR netblock
pairs. Each netblock pair is evaluated in order against the IP
addresses. If the IP address in the packet matches the first
netblock, it is rewritten using the second netblock as a mask
against the high order bits.
IPv4 Example:
--pnat=192.168.0.0/16:10.77.0.0/16,172.16.0.0/12:10.1.0.0/24
IPv6 Example:
--pnat=[2001:db8::/32]:[dead::/16],[2001:db8::/32]:[::ffff:0:0/96]
-S string, --srcipmap=string
Rewrite source IPv4/v6 addresses using pseudo-NAT. This option
may appear up to 1 times. This option must not appear in combi‐
nation with any of the following options: pnat.
Works just like the --pnat option, but only affects the source
IP addresses in the IPv4/v6 header.
-D string, --dstipmap=string
Rewrite destination IPv4/v6 addresses using pseudo-NAT. This
option may appear up to 1 times. This option must not appear in
combination with any of the following options: pnat.
Works just like the --pnat option, but only affects the destina‐
tion IP addresses in the IPv4/v6 header.
-e string, --endpoints=string
Rewrite IP addresses to be between two endpoints. This option
may appear up to 1 times. This option must appear in combina‐
tion with the following options: cachefile.
Takes a pair of colon delimited IPv4/v6 addresses which will be
used to rewrite all traffic to appear to be between the two IP
addresses.
IPv4 Example:
--endpoints=172.16.0.1:172.16.0.2
IPv6 Example:
--endpoints=[2001:db8::dead:beef]:[::ffff:0:0:ac:f:0:2]
-b, --skipbroadcast
Skip rewriting broadcast/multicast IPv4/v6 addresses.
By default --seed, --pnat and --endpoints will rewrite broadcast
and multicast IPv4/v6 and MAC addresses. Setting this flag will
keep broadcast/multicast IPv4/v6 and MAC addresses from being
rewritten.
-C, --fixcsum
Force recalculation of IPv4/TCP/UDP header checksums.
Causes each IPv4/v6 packet to have their checksums recalculated
and fixed. Automatically enabled for packets modified with
--seed, --pnat, --endpoints or --fixlen.
-m number, --mtu=number
Override default MTU length (1500 bytes). This option may
appear up to 1 times. This option takes an integer number as
its argument. The value of number is constrained to being:
in the range 1 through MAXPACKET
Override the default 1500 byte MTU size for determining the max‐
imum padding length (--fixlen=pad) or when truncating (--mtu-
trunc).
--mtu-trunc
Truncate packets larger then specified MTU. This option may
appear up to 1 times.
Similar to --fixlen, this option will truncate data in packets
from Layer 3 and above to be no larger then the MTU.
-E, --efcs
Remove Ethernet checksums (FCS) from end of frames.
Note, this option is pretty dangerous! We do not actually check
to see if a FCS actually exists in the frame, we just blindly
delete the last 4 bytes. Hence, you should only use this if you
know know that your OS provides the FCS when reading raw pack‐
ets.
--ttl=string
Modify the IPv4/v6 TTL/Hop Limit.
Allows you to modify the TTL/Hop Limit of all the IPv4/v6 pack‐
ets. Specify a number to hard-code the value or +/-value to
increase or decrease by the value provided (limited to 1-255).
Examples:
--ttl=10
--ttl=+7
--ttl=-64
--tos=number
Set the IPv4 TOS/DiffServ/ECN byte. This option may appear up
to 1 times. This option takes an integer number as its argu‐
ment. The value of number is constrained to being:
in the range 0 through 255
Allows you to override the TOS (also known as DiffServ/ECN)
value in IPv4.
--tclass=number
Set the IPv6 Traffic Class byte. This option may appear up to 1
times. This option takes an integer number as its argument.
The value of number is constrained to being:
in the range 0 through 255
Allows you to override the IPv6 Traffic Class field.
--flowlabel=number
Set the IPv6 Flow Label. This option may appear up to 1 times.
This option takes an integer number as its argument. The value
of number is constrained to being:
in the range 0 through 1048575
Allows you to override the 20bit IPv6 Flow Label field. Has no
effect on IPv4 packets.
-F string, --fixlen=string
Pad or truncate packet data to match header length. This option
may appear up to 1 times.
Packets may be truncated during capture if the snaplen is
smaller then the packet. This option allows you to modify the
packet to pad the packet back out to the size stored in the
IPv4/v6 header or rewrite the IP header total length to reflect
the stored packet length.
pad Truncated packets will be padded out so that the packet
length matches the IPv4 total length
trunc Truncated packets will have their IPv4 total length field
rewritten to match the actual packet length
del Delete the packet
--fuzz-seed=number
Fuzz 1 in X packets. Edit bytes, length, or emulate packet drop.
This option takes an integer number as its argument. The value
of number is constrained to being:
greater than or equal to 0
The default number for this option is:
0
This fuzzing was designed as to test layer 7 protocols such as
voip protocols. It modifies randomly 1 out of X packets (where
X = --fuzz-factor) in order for stateful protocols to cover more
of their code. The random fuzzing actions focus on data start
and end because it often is the part of the data application
protocols base their decisions on.
Possible fuzzing actions list:
* drop packet
* reduce packet size
* edit packet Bytes:
* Not all Bytes have the same probability of appearance in
real life.
Replace with 0x00, 0xFF, or a random byte with equal like‐
lyhook
* Not all Bytes have the same significance in a packet.
Replace the start, the end, or the middle of the packet
with equal likelihood.
* do nothing (7 out of 8 packets)
--fuzz-factor=number
Set the Fuzz 1 in X packet ratio (default 1 in 8 packets). This
option must appear in combination with the following options:
fuzz-seed. This option takes an integer number as its argument.
The value of number is constrained to being:
greater than or equal to 1
The default number for this option is:
8
Sets the ratio of for --fuzz-seed option. By default this value
is 8, which means 1 in 8 packets are modified by fuzzing. Note
that this ratio is based on the random number genereated by the
supplied fuzz seed. Therefore by default you cannot expect that
exactly every eighth packet will be modified.
--skipl2broadcast
Skip rewriting broadcast/multicast Layer 2 addresses.
By default, editing Layer 2 addresses will rewrite broadcast and
multicast MAC addresses. Setting this flag will keep broad‐
cast/multicast MAC addresses from being rewritten.
--dlt=string
Override output DLT encapsulation. This option may appear up to
1 times.
By default, no DLT (data link type) conversion will be made. To
change the DLT type of the output pcap, select one of the fol‐
lowing values:
enet Ethernet aka DLT_EN10MB
hdlc Cisco HDLC aka DLT_C_HDLC
jnpr_ether Juniper Ethernet DLT_C_JNPR_ETHER
pppserial PPP Serial aka DLT_PPP_SERIAL
user User specified Layer 2 header and DLT type
--enet-dmac=string
Override destination ethernet MAC addresses. This option may
appear up to 1 times.
Takes a pair of comma deliminated ethernet MAC addresses which
will replace the destination MAC address of outbound packets.
The first MAC address will be used for the server to client
traffic and the optional second MAC address will be used for the
client to server traffic.
Example:
--enet-dmac=00:12:13:14:15:16,00:22:33:44:55:66
--enet-smac=string
Override source ethernet MAC addresses. This option may appear
up to 1 times.
Takes a pair of comma deliminated ethernet MAC addresses which
will replace the source MAC address of outbound packets. The
first MAC address will be used for the server to client traffic
and the optional second MAC address will be used for the client
to server traffic.
Example:
--enet-smac=00:12:13:14:15:16,00:22:33:44:55:66
--enet-subsmac=string
Substitute MAC addresses. This option may appear up to 9999
times.
Allows you to rewrite ethernet MAC addresses of packets. It
takes comma delimited pair or MACs address and rewrites all
occurrences of the first MAC with the value of the second MAC.
Example:
--enet-subsmac=00:12:13:14:15:16,00:22:33:44:55:66
--enet-mac-seed=number
Randomize MAC addresses. This option may appear up to 1 times.
This option must not appear in combination with any of the fol‐
lowing options: enet-smac, enet-dmac, enet-subsmac. This option
takes an integer number as its argument.
Allows you to randomize ethernet MAC addresses of packets,
mostly like what --seed option does for IPv4/IPv6 addresses.
--enet-mac-seed-keep-bytes=number
Randomize MAC addresses. This option may appear up to 1 times.
This option must appear in combination with the following
options: enet-mac-seed. This option takes an integer number as
its argument. The value of number is constrained to being:
in the range 1 through 6
Keep some bytes untouched when usinging --enet-mac-seed option.
--enet-vlan=string
Specify ethernet 802.1q VLAN tag mode. This option may appear
up to 1 times.
Allows you to rewrite ethernet frames to add a 802.1q header to
standard 802.3 ethernet headers or remove the 802.1q VLAN tag
information.
add Rewrites the existing 802.3 ethernet header as an 802.1q
VLAN header
del Rewrites the existing 802.1q VLAN header as an 802.3 ether‐
net header
--enet-vlan-tag=number
Specify the new ethernet 802.1q VLAN tag value. This option may
appear up to 1 times. This option must appear in combination
with the following options: enet-vlan. This option takes an
integer number as its argument. The value of number is con‐
strained to being:
in the range 0 through 4095
--enet-vlan-cfi=number
Specify the ethernet 802.1q VLAN CFI value. This option may
appear up to 1 times. This option must appear in combination
with the following options: enet-vlan. This option takes an
integer number as its argument. The value of number is con‐
strained to being:
in the range 0 through 1
--enet-vlan-pri=number
Specify the ethernet 802.1q VLAN priority. This option may
appear up to 1 times. This option must appear in combination
with the following options: enet-vlan. This option takes an
integer number as its argument. The value of number is con‐
strained to being:
in the range 0 through 7
--hdlc-control=number
Specify HDLC control value. This option may appear up to 1
times. This option takes an integer number as its argument.
The Cisco HDLC header has a 1 byte "control" field. Apparently
this should always be 0, but if you can use any 1 byte value.
--hdlc-address=number
Specify HDLC address. This option may appear up to 1 times.
This option takes an integer number as its argument.
The Cisco HDLC header has a 1 byte "address" field which has two
valid values:
0x0F Unicast
0xBF Broadcast
You can however specify any single byte value.
--user-dlt=number
Set output file DLT type. This option may appear up to 1 times.
This option takes an integer number as its argument.
Set the DLT value of the output pcap file.
--user-dlink=string
Rewrite Data-Link layer with user specified data. This option
may appear up to 2 times.
Provide a series of comma deliminated hex values which will be
used to rewrite or create the Layer 2 header of the packets.
The first instance of this argument will rewrite both server and
client traffic, but if this argument is specified a second time,
it will be used for the client traffic.
Example:
--user-dlink=01,02,03,04,05,06,00,1A,2B,3C,4D,5E,6F,08,00
-d number, --dbug=number
Enable debugging output. This option may appear up to 1 times.
This option takes an integer number as its argument. The value
of number is constrained to being:
in the range 0 through 5
The default number for this option is:
0
If configured with --enable-debug, then you can specify a ver‐
bosity level for debugging output. Higher numbers increase ver‐
bosity.
-i string, --intf1=string
Primary interface (listen in uni-directional mode). This option
may appear up to 1 times.
-I string, --intf2=string
Secondary interface (send in uni-directional mode). This option
may appear up to 1 times.
-u, --unidir
Send and receive in only one direction. This option may appear
up to 1 times.
Normally, tcpbridge will send and receive traffic in both direc‐
tions (bi-directionally). However, if you choose this option,
traffic will be sent uni-directionally.
--listnics
List available network interfaces and exit.
-L number, --limit=number
Limit the number of packets to send. This option may appear up
to 1 times. This option takes an integer number as its argu‐
ment. The value of number is constrained to being:
greater than or equal to 1
The default number for this option is:
-1
By default, tcpbridge will send packets forever or until Ctrl-C.
Alternatively, you can specify a maximum number of packets to
send.
-M string, --mac=string
MAC addresses of local NIC's. This option may appear up to 2
times.
tcpbridge does not support detecting the MAC addresses of the
local network interfaces under Windows. Please specify both MAC
addresses of the interfaces used in the bridge: -M <intf1 mac>
-M <intf2 mac>
-x string, --include=string
Include only packets matching rule. This option may appear up
to 1 times. This option must not appear in combination with any
of the following options: exclude.
Override default of sending all packets stored in the capture
file and only send packets which match the provided rule. Rules
can be one of:
S:<CIDR1>,... - Source IP must match specified CIDR(s)
D:<CIDR1>,... - Destination IP must match specified CIDR(s)
B:<CIDR1>,... - Both source and destination IP must match spec‐
ified CIDR(s)
E:<CIDR1>,... - Either IP must match specified CIDR(s)
P:<LIST> - Must be one of the listed packets where the list cor‐
responds to the packet number in the capture file.
--include=P:1-5,9,15,72-
would send packets 1 thru 5, the 9th and 15th packet, and pack‐
ets 72 until the end of the file
F:'<bpf>' - BPF filter. See the tcpdump(8) man page for syntax.
-X string, --exclude=string
Exclude any packet matching this rule. This option may appear
up to 1 times. This option must not appear in combination with
any of the following options: include.
Override default of sending all packets stored in the capture
file and only send packets which do not match the provided rule.
Rules can be one of:
S:<CIDR1>,... - Source IP must not match specified CIDR(s)
D:<CIDR1>,... - Destination IP must not match specified CIDR(s)
B:<CIDR1>,... - Both source and destination IP must not match
specified CIDR(s)
E:<CIDR1>,... - Either IP must not match specified CIDR(s)
P:<LIST> - Must not be one of the listed packets where the list
corresponds to the packet number in the capture file.
--exclude=P:1-5,9,15,72-
would drop packets 1 thru 5, the 9th and 15th packet, and pack‐
ets 72 until the end of the file
-P, --pid
Print the PID of tcpbridge at startup.
-v, --verbose
Print decoded packets via tcpdump to STDOUT. This option may
appear up to 1 times.
-A string, --decode=string
Arguments passed to tcpdump decoder. This option may appear up
to 1 times. This option must appear in combination with the
following options: verbose.
When enabling verbose mode (-v) you may also specify one or more
additional arguments to pass to tcpdump to modify the way pack‐
ets are decoded. By default, -n and -l are used. Be sure to
quote the arguments like: --verbose="-axxx" so that they are not
interpreted by tcpbridge. The following arguments are valid:
[ -aAeNqRStuvxX ]
[ -E spi@ipaddr algo:secret,... ]
[ -s snaplen ]
-V, --version
Print version information.
-h, --less-help
Display less usage information and exit.
-H, --help
Display usage information and exit.
-!, --more-help
Pass the extended usage information through a pager.
--save-opts [=cfgfile]
Save the option state to cfgfile. The default is the last con‐
figuration file listed in the OPTION PRESETS section, below.
The command will exit after updating the config file.
--load-opts=cfgfile, --no-load-opts
Load options from cfgfile. The no-load-opts form will disable
the loading of earlier config/rc/ini files. --no-load-opts is
handled early, out of order.
OPTION PRESETS
Any option that is not marked as not presettable may be preset by load‐
ing values from configuration ("RC" or ".INI") file(s). The homerc
file is "$$/", unless that is a directory. In that case, the file
".tcpbridgerc" is searched for within that directory.
FILES
See OPTION PRESETS for configuration files.
EXIT STATUS
One of the following exit values will be returned:
0 (EXIT_SUCCESS)
Successful program execution.
1 (EXIT_FAILURE)
The operation failed or the command syntax was not valid.
66 (EX_NOINPUT)
A specified configuration file could not be loaded.
70 (EX_SOFTWARE)
libopts had an internal operational error. Please report it to
autogen-users@lists.sourceforge.net. Thank you.
AUTHORS
Copyright 2013-2017 Fred Klassen - AppNeta Copyright 2000-2012 Aaron
Turner For support please use the tcpreplay-users@lists.sourceforge.net
mailing list. The latest version of this software is always available
from: http://tcpreplay.appneta.com/
COPYRIGHT
Copyright (C) 2000-2017 Aaron Turner and Fred Klassen all rights
reserved. This program is released under the terms of the GNU General
Public License, version 3 or later.
BUGS
Please send bug reports to: tcpreplay-users@lists.sourceforge.net
NOTES
This manual page was AutoGen-erated from the tcpbridge option defini‐
tions.
tcpbridge 16 May 2017 tcpbridge(1)
