mimic run

-q, --quiet

Output less information

-v, --verbose

Output more information

-f, --filter=FILTER

Specify what packets to process. This may be specified for multiple times. (see CONFIGURATION/Filters)

-L, --link-type=TYPE

Specify link layer type, can be 'eth' (Ethernet) or 'none' (no L2 header, like PPP or TUN). Defaults to 'eth'.

-x, --xdp-mode

Force XDP attach mode, either 'skb' or 'native'. Defaults to 'native' if target interface supports it, or 'skb'.

-X, --use-libxdp

Use libxdp instead of libbpf to load XDP program. libxdp supports chaining multiple XDP programs on one interface. Mimic loads libxdp dynamically using dlopen. Only available when built with USE_LIBXDP=1.

-h, --handshake

Controls retry behaviour of initiating connection (see CONFIGURATION/Handshake and Keepalive Parameters)

-k, --keepalive

Controls keepalive mechanism (see CONFIGURATION/Handshake and Keepalive Parameters)

-p, --padding

Padding size appended to each packet. Pass 'random' to use random padding.

-W, --max-window

Always use maximum window size in TCP packets.

-F, --file=PATH

Load configuration from file

mimic show

-c, --connections

Show connections

-p, --process

Show process information

Filters

A filter is an entry of whitelist that looks like a key-value pair: {origin}={ip}:{port}. Origin is either local or remote, indicating which side's IP and port is matched. For example, remote=192.0.2.1:6000 matches the server's IP (192.0.2.1) and its listening port (6000).

For IPv6, the IP field needs to be surrounded by square brackets: local=[2001:db8::cafe]:7000. This means packets originated from or sending to the local machine using that IP and port is processed.

Additionally, settings that overrides global ones can be appended to the back of a filter, such as padding as well as handshake and keepalive parameters (see Handshake and Keepalive Parameters):

local=[fd42:d42:d42:d42::1]:20001,keepalive=60:1:3:1000
remote=169.254.42.1:11451,handshake=3:3,keepalive=:1::
local=192.0.2.1:4242,padding=8

Handshake and Keepalive Parameters

Handshake and keepalive parameters are both specified using unsigned numbers separated by colons (:). Duration fields are specified in seconds.

Handshake parameters interval:retry specifies:

• interval: Duration between each handshake (SYN) retry. Defaults to 2. interval of 0 makes all connections through this filter passive, i.e. Mimic will not initiate connection on this side.
• retry: Maximum retry count before giving up. Defaults to 3. retry of 0 means connection resets after first handshake packet does not have response in interval seconds.

Keepalive parameters time:interval:retry:stale specifies:

• time: Duration between last peer activity (i.e. receiving packets) and sending keepalive. Defaults to 180 (3 minutes). time of 0 turns off keepalive mechanism. If underlying UDP protocol implements keepalive (e.g. tunnel protocols like WireGuard), it is advised to set this value higher than the protocol's keepalive time.
• interval: Duration between keepalive attempt without peer acknowledgement. Defaults to 10. interval of 0 disables keepalive and resets immediately after time has passed.
• retry: Maximum retry count before giving up. Defaults to 3. retry of 0 means connection resets after first keepalive packet does not have response in interval seconds.
• stale: Duration between last underlying activity and reset, disregarding keepalive packets. Defaults to 600 (10 minutes). This is useful when using remote filter, and the local port changes due to service restart or connection retry, leaving previous connections captured by Mimic unused.

Numbers can be left out to fall back to default or global respective values:

handshake=:0     # give up immediately after default interval value and do not retry
keepalive=60:::  # set keepalive time to 60s only, keeping default values of other fields

Configuration File

Configuration file passed using the --file contains lines of key-value pair in the format of {key}={value}. There might be spaces between key, = and value. Each pair should be contained in one line:

# Print more information because we can
log.verbosity = trace
# Keep it more alive!
keepalive = 15:::
# You only shake hands once
filter = local=192.0.2.1:6789,handshake=5:0

See /usr/share/doc/mimic/eth0.conf.example for detailed examples.

Available Configuration Keys

log.verbosity

Controls how much information should be printed. Log level equal to or higher (in number) than log verbosity will be discarded. Both number and string matching log levels are accepted. Number must be greater than or equal to 0. Defaults to info (2). Available levels are: 0 - error (cannot be discarded), 1 - warn, 2 - info, 3 - debug, 4 - trace.

link_type, xdp_mode, use_libxdp, handshake, keepalive, padding, max_window

See OPTIONS.

filter

See Filters. This option may be specified more than once.