Manual:IP/Firewall/Connection tracking

Connection tracking entries

Sub-menu: /ip firewall connection

There are several ways to see what connections are making their way though the router.

In the Winbox Firewall window, you can switch to the Connections tab, to see current connections to/from/through your router. It looks like this:

Properties

All properties in connection list are read-only

Property	Description
assured (yes | no)	"assured" flag indicates that this connection is assured and that it will not be erased if maximum possible tracked connection count is reached.
confirmed (yes | no)
connection-mark (string)	connection mark set by mangle rule.
connection-type (pptp | ftp)	Type of connection, property is empty if connection tracking is unable to determine predefined connection type.
dst-address (ip[:port])	Destination address and port (if protocol is port based).
dstnat (yes | no)	Connection has gone through DST-NAT (for example, port forwarding).
dying (yes | no)
expected (yes | no)
fasttrack (yes | no)	Whether the connection is FastTracked.
gre-key (integer)
gre-protocol (string)
gre-version (string)
icmp-code (string)	ICMP Code Field
icmp-id (integer)
icmp-type (integer)	ICMP Type Number
orig-bytes (integer)	Amount of bytes sent out from the source address using the specific connection.
orig-fasttrack-bytes (integer)	Amount of FastTracked bytes sent out from the source address using the specific connection.
orig-fasttrack-packets (integer)	Amount of FastTracked packets sent out from the source address using the specific connection.
orig-packets (integer)	Amount of packets sent out from the source address using the specific connection.
orig-rate (integer)	Data rate at which packets are sent out from the source address using the specific connection.
protocol (string)	IP protocol type
repl-bytes (integer)	Amount of bytes received from the destination address using the specific connection.
repl-fasttrack-bytes (string)	Amount of FastTracked bytes received from the destination address using the specific connection.
repl-fasttrack-packets (integer)	Amount of FastTracked packets received from the destination address using the specific connection.
repl-packets (integer)	Amount of packets received from the destination address using the specific connection.
repl-rate (string)	Data rate at which packets are received from the destination address using the specific connection.
reply-dst-address (ip[:port])	Destination address (and port) expected of return packets. Usually the same as "src-address:port"
reply-src-address (ip[:port])	Source address (and port) expected of return packets. Usually the same as "dst-address:port"
seen-reply (yes | no)	Destination address has replied to the source address.
src-address (ip[:port])	Source address and port (if protocol is port based).
srcnat (yes | no)	Connection is going through SRC-NAT, including packets that were masqueraded through NAT.
tcp-state (string)	Current state of TCP connection : "established" "time-wait" "close" "syn-sent" "syn-received"
timeout (time)	Time after connection will be removed from connection list.

Connection tracking settings

Sub-menu: /ip firewall connection tracking

Properties

Property	Description
enabled (yes | no | auto; Default: auto)	Allows to disable or enable connection tracking. Disabling connection tracking will cause several firewall features to stop working. See the list of affected features. Starting from v6.0rc2 default value is auto. Which means that connection tracing is disabled until at least one firewall rule is added.
tcp-syn-sent-timeout (time; Default: 5s)	TCP SYN timeout.
tcp-syn-received-timeout (time; Default: 5s)	TCP SYN timeout.
tcp-established-timeout (time; Default: 1d)	Time when established TCP connection times out.
tcp-fin-wait-timeout (time; Default: 10s)
tcp-close-wait-timeout (time; Default: 10s)
tcp-last-ack-timeout (time; Default: 10s)
tcp-time-wait-timeout (time; Default: 10s)
tcp-close-timeout (time; Default: 10s)
udp-timeout (time; Default: 10s)	Specifies the timeout for udp connections that has seen packets in one direction
udp-stream-timeout (time; Default: 3m)	Specifies the timeout of udp connections that has seen packets in both directions
icmp-timeout (time; Default: 10s)	ICMP connection timeout
generic-timeout (time; Default: 10m)	Timeout for all other connection entries

Read-only properties

Property	Description
max-entries (integer)	Max amount of entries that connection tracking table can hold. This value depends on installed amount of RAM. Note that system does not create maximum size connection tracking table when it starts, maximum entry amount can increase if situation demands it and router still has free ram left.
total-entries (integer)	Amount of connections that currently connection table holds.

Features affected by connection tracking

• NAT
• firewall:
  • connection-bytes
  • connection-mark
  • connection-type
  • connection-state
  • connection-limit
  • connection-rate
  • layer7-protocol
  • p2p
  • new-connection-mark
  • tarpit