Here’s how to check if port is listening on a Windows Server.
Log in to the destination server.
netstat -ano | find "443" | find "LISTEN" tasklist /fi "PID eq "443" |
cloud engineer
Here’s how to check if port is listening on a Windows Server.
Log in to the destination server.
netstat -ano | find "443" | find "LISTEN" tasklist /fi "PID eq "443" |
netstat -ano | find "443" | find "LISTEN" tasklist /fi "PID eq "443"
Promiscuous mode is a mode for a network interface where the controller to passes all traffic it receives to the CPU instead of passing the frames to the controller. This is helpful if you want to capture all traffic as part of troubleshooting. The question is, how can you tell if your network interface is in a promiscuous mode? Here’s a couple of commands.
Here’s the default mode.
sudo ip link show eth0 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1460 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff |
sudo ip link show eth0 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1460 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
Here’s promiscuous mode. Look for PROMISC.
sudo ip link show eth0 2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1460 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff |
sudo ip link show eth0 2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1460 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
The other command is netstat. Look for P flag.
netstat -i Kernel Interface table Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg eth0 1460 21895816 0 0 0 22645756 0 0 0 BMPRU lo 65536 44129 0 0 0 44129 0 0 0 LRU |
netstat -i Kernel Interface table Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg eth0 1460 21895816 0 0 0 22645756 0 0 0 BMPRU lo 65536 44129 0 0 0 44129 0 0 0 LRU
Finally, if you want to enable promiscuous mode, run one of these commands.
sudo ip link set eth0 promisc on ifconfig eth0 promisc |
sudo ip link set eth0 promisc on ifconfig eth0 promisc
To disable, use ifconfig.
ifconfig eth0 -promisc |
ifconfig eth0 -promisc
Netstat is a utility for gathering network statistics. It comes preinstalled on most systems.
If missing, here’s how to install.
# Redhat, CentOS yum install net-tools # Debian, Ubuntu, Mint apt install net-tools # SLES, SUSE zypper install net-tools |
# Redhat, CentOS yum install net-tools # Debian, Ubuntu, Mint apt install net-tools # SLES, SUSE zypper install net-tools
Here are some common and useful commands.
# show version netstat -v # show routing table netstat -nr # show network interface statistics netstat -ai # show network connections netstat -ant # show network services netstat -tulpn |
# show version netstat -v # show routing table netstat -nr # show network interface statistics netstat -ai # show network connections netstat -ant # show network services netstat -tulpn
If you’re running a Linux server, here’s one way of checking as to which ports are open to the public. You can use netstat for that purpose. Netstat is a command-line network utility tool that displays network connections for tcp, routing tables, and a number of network interfaces. It’s available on Linux, MacOS and Windows.
In Linux and MacOS, type the following via the Terminal.
netstat -tupln # # -l = only services which are listening on some port # -n = show port number, don't try to resolve the service name # -t = tcp ports # -u = udp ports # -p = name of the program # |
netstat -tupln # # -l = only services which are listening on some port # -n = show port number, don't try to resolve the service name # -t = tcp ports # -u = udp ports # -p = name of the program #
If you’re in Windows, open up Powershell and type in:
netstat -ano | find "LISTENING" # or netstat -o 5 |
netstat -ano | find "LISTENING" # or netstat -o 5
Don’t be surprised as to what your computer is doing.