Lists active network ports and protocols over time

Numid

8/30/24, 1:25 PM

Is there a linux server utility that can list the network ports and protocols that have been active over a given period of time?

For example, I'd like to know which ports and protocols were active at least once last week. The answer would be something like: TCP/80, TCP/443, UDP/5678...

1 + 2

networking

linux

sysadmin

jcaron

8/30/24, 11:30 PM

What do you mean by "active"? A process was listening on one of those ports? There was an incoming connection on one of those ports? A process connected to that port on a remote server? Something else?

Numid

9/1/24, 5:20 PM

I mean that incoming connections have occurred.

Score:3

Server

Romeo Ninov

8/30/24, 1:49 PM

You can install and activate auditd. Add there rules in audit config:

-a always,exit -F arch=b64 -S connect -F key=CONNECT
-a always,exit -F arch=b64 -S bind -F key=BIND
-a always,exit -F arch=b64 -S socket -F key=SOCKET
-a always,exit -F arch=b64 -S listen -F key=LISTEN
-a always,exit -F arch=b64 -S shutdown -F key=SHUTDOWN
-a always,exit -F arch=b64 -S close -F key=CLOSE

and you will have in audit logs you can monitor socket related system calls.

If you want to find now old information (and do not have audit) I do not think you will find relevant information in linux.

+ 2

Numid

9/1/24, 8:55 AM

Thank you. That utility seems to be a good fit for monitoring the socket activity of the server. However, the log it produces is dense. How can I extract the desired information? Digging a little bit deeper, I have found https://www.linkedin.com/pulse/using-auditd-monitor-network-connections-alex-maestretti/ along with https://twiki.cern.ch/twiki/bin/view/LinuxSupport/IDSNetConnectionLogger. Still, I can't make my way out of it.

Romeo Ninov

9/1/24, 9:16 AM

@Numid, you can filter by using `key` value directly from `audit`. And then filter by port, IP, etc

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