2020年8月15日 · Conntrack functionality is a Linux kernel module, and it is often included in the kernel in default configuration. Conntrack operation can be tuned by adjusting net.netfilter.nf_conntrack sysctl values. Your second alternative is what happens.

2022年10月18日 · When such a packet arrives, it sets a flag on the packet, that is belongs to some "known" connection. Then, the -m conntrack --ctstate ESTABLISHED in the firewall uses that flag and it will match any of those "known" packets. This way, you can match precisely replies to your outgoing packets, without even knowing in advance what they are, at ...

2017年4月20日 · The program reads its information from /proc/net/ip_conntrack or /proc/net/nf_conntrack, which is the temporary conntrack-storage of netfilter. You just need to take care of logging its output and monitoring it.

I'm trying to get outgoing IPv6 routing going, my issue is, that conntrack is not working correctly. I've dumped the traffic via tcpdump, which shows me that the packets go outside (e.g. internal interface -> router -> isp) and that I receive a response (isp -> router).

2011年11月7日 · Conntrack just enables you to view and manipulate the stateful data about connections. It doesn't manipulate the the TCP packets flowing as part of that ssh connection. If you want to break the ssh session, and you just delete that connection's state data, a new connection will begin being tracked.

2024年4月24日 · "nf_conntrack: table full, dropping packet" even though nf_conntrack_count is much less than nf_conntrack_max I have a node in our cluster which gets lots of "nf_conntrack: table full, dropping packet" messages in the syslog.

So, to answer the question, conntrack is for use with the conntrack toolkit and supersedes state in this regard. It is better than state if you are planning on using the conntrack tool kit. Connection tracking is on for traffic flows, it constantly tries to match flows to rules. The answer that follows for question 2 is, yes, use conntrack

The reply by Ethan Xu is one solution, but if you don't want to load nf_conntrack at boot, you can set nf_conntrack_max later upon module load, as documented by sysctl and already proposed in a systemd issue:

After 'conntrack -D', the NAT works as expected again. I'd like to delete only the conntrack entries belonging to the old external address or to solve the problem in a way that wouldn't affect connections through other interfaces. E.g. - I'd like to delete all conntrack entries having reverse connection destination dst=old.ext.ip.adr, like

conntrack -L Dump the connection tracking table in /proc/net/ip_conntrack format so i found the log file in /proc/net/ip_conntrack and it updates at realtime on every ip conntrack, but when i type 'conntrack' i get not found. its a d-link router with Linux version 2.4.20