firehol-connmark - set a stateful mark from the connmark group


{ connmark | connmark46 } value chain rule-params

connmark4 value chain rule-params

connmark6 value chain rule-params


Marks on packets can be matched by traffic shaping, routing, and firewall rules for controlling traffic.

Note Behaviour changed significantly in FireHOL v3 compared to earlier versions

FireHOL uses iptables masks to break the single 32-bit integer mark value into smaller groups and allows you to set and match them independently. The markdef group definitions to set this up are found in firehol-defaults.conf

The connmark helper command sets values within the connmark group. You can set value between 0 (no mark) and size-1. The default size for connmark is 64, so 63 is highest value possible. The default connmark types are stateful+permanent, meaning the initial match will only be done on NEW packets and the mark will be restored to all packets in the connection.

The chain will be used to find traffic to mark. It can be any of the iptables(8) built in chains belonging to the mangle table. The chain names are: INPUT, FORWARD, OUTPUT, PREROUTING and POSTROUTING. The names are case-sensitive.

The rule-params define a set of rule parameters to match the traffic that is to be marked within the chosen chain. See firehol-params(5) for more details.

Any connmark commands must be declared before the first router or interface.


If you want to do policy based routing based on iptables(8) marks, you will need to disable the Root Path Filtering on the interfaces involved (rp_filter in sysctl).

FireQOS will read the FireHOL mark definitions and set up suitable offsets and marks for the various groups. If you are using a different tool, you should look at the emitted firewall to determine the final masks and values to use.


# mark with 1, packets sent by the local machine
 connmark 1 OUTPUT

 # mark with 2, packets routed by the local machine
 connmark 2 FORWARD

 # mark with 3, packets routed by the local machine, sent from
 #     destined for port TCP/25 of
 connmark 3 FORWARD proto tcp dport 25 dst src