netstat -tn
-n: Display numeric only
-t: Display TCP connections only
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| Who is connecting to linux host: netstat -tn |
netstat is not installed on CentOS/RHEL minimal installation by default.
[tuyendq@001 ~]$ which netstat /usr/bin/which: no netstat in (/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/tuyendq/.local/bin:/home/tuyendq/bin)
Which package does netstat belong to?
[tuyendq@001 ~]$ yum search netstat Loaded plugins: fastestmirror Determining fastest mirrors * base: mirror.hostduplex.com * epel: mirrors.develooper.com * extras: repos.lax.quadranet.com * updates: mirror.hostduplex.com zabbix-non-supported 4/4 =================================================== Matched: netstat =================================================== bwm-ng.x86_64 : Bandwidth Monitor NG dstat.noarch : Versatile resource statistics tool net-snmp.x86_64 : A collection of SNMP protocol tools and libraries net-tools.x86_64 : Basic networking tools python2-psutil.x86_64 : A process and system utilities module for Python python34-psutil.x86_64 : A process and system utilities module for Python python36-psutil.x86_64 : A process and system utilities module for Python unhide.x86_64 : Tool to find hidden processes and TCP/UDP ports from rootkits
Install net-tools package in order to use netstat
[tuyendq@001 ~]$ sudo yum install -y net-tools [sudo] password for tuyendq: Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: mirror.scalabledns.com * epel: mirrors.develooper.com * extras: mirror.scalabledns.com * updates: mirrors.usc.edu Resolving Dependencies --> Running transaction check ---> Package net-tools.x86_64 0:2.0-0.24.20131004git.el7 will be installed --> Finished Dependency Resolution Dependencies Resolved ======================================================================================================================== Package Arch Version Repository Size ======================================================================================================================== Installing: net-tools x86_64 2.0-0.24.20131004git.el7 base 306 k Transaction Summary ======================================================================================================================== Install 1 Package Total download size: 306 k Installed size: 918 k Downloading packages: net-tools-2.0-0.24.20131004git.el7.x86_64.rpm | 306 kB 00:00:01 Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : net-tools-2.0-0.24.20131004git.el7.x86_64 1/1 Verifying : net-tools-2.0-0.24.20131004git.el7.x86_64 1/1 Installed: net-tools.x86_64 0:2.0-0.24.20131004git.el7 Complete!
Check netstat version
[tuyendq@001 ~]$ netstat --version net-tools 2.10-alpha Fred Baumgarten, Alan Cox, Bernd Eckenfels, Phil Blundell, Tuan Hoang, Brian Micek and others +NEW_ADDRT +RTF_IRTT +RTF_REJECT +FW_MASQUERADE +I18N +SELINUX AF: (inet) +UNIX +INET +INET6 +IPX +AX25 +NETROM +X25 +ATALK +ECONET +ROSE -BLUETOOTH HW: +ETHER +ARC +SLIP +PPP +TUNNEL -TR +AX25 +NETROM +X25 +FR +ROSE +ASH +SIT +FDDI +HIPPI +HDLC/LAPB +EUI64 [tuyendq@001 ~]$
Check open ports with netstat, ss, lsof
netstat -tupln | grep LISTEN sudo ss -tupln | grep LISTEN sudo lsof -i -P -n | grep LISTEN