View Network Ports in Linux

View Network Ports in Linux

Briefly summarize the results of learning Linux in the past.

 

Check whether TCP 22 is enabled. 1. List all ports: [root @ Demon proc] # netstat-ntlpActive Internet connections (only servers) Proto...

1. Check whether port TCP 22 is enabled.

1. List all ports:

[Root @ Demon proc] # netstat-ntlp

Active Internet connections (only servers)

Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name

Tcp 0 0 0.0.0.0: 111 0.0.0.0: * LISTEN 1634/rpcbind

Tcp 0 0 0.0.0.0: 8080 0.0.0.0: * LISTEN 13888/nginx

Tcp 0 0 0.0.0.0: 22 0.0.0.0: * LISTEN 1960/sshd

Tcp 0 0 127.0.0.1: 631 0.0.0.0: * LISTEN 1823/cupsd

Tcp 0 0 127.0.0.1: 25 0.0.0.0: * LISTEN 2359/master

Tcp 0 0 0.0.0.0: 52771 0.0.0.0: * LISTEN 1779/rpc. statd

Tcp 0 0 0.0.0.0: 3306 0.0.0.0: * LISTEN 2263/mysqld

Tcp 0 0: 111: * LISTEN 1634/rpcbind

Tcp 0 0: 22: * LISTEN 1960/sshd

Tcp 0 0: 1: 631: * LISTEN 1823/cupsd

Tcp 0 0: 1: 25: * LISTEN 2359/master

Tcp 0 0: 52072: * LISTEN 1779/rpc. statd

2. There are two methods to view the TCP 22 Port:

# Method 1

[Root @ Demon proc] # netstat-ntlp | grep 22

Tcp 0 0 0.0.0.0: 22 0.0.0.0: * LISTEN 1960/sshd

Tcp 0 0 0.0.0.0: 3306 0.0.0.0: * LISTEN 2263/mysqld

Tcp 0 0: 22: * LISTEN 1960/sshd

# Method 2

[Root @ Demon proc] # lsof-I tcp: 22

Command pid user fd type device size/OFF NODE NAME

Sshd 1960 root 3u IPv4 14435 0t0 TCP *: ssh (LISTEN)

Sshd 1960 root 4u IPv6 14441 0t0 TCP *: ssh (LISTEN)

Ii. Network Configuration

1. static IP settings

# First, open the NIC configuration file:

[Root @ Demon proc] # vim/etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE = eth0 # specify the DEVICE name

UUID = 1bc2ebe3-0b0c-4a67-89eb-9214a7bd97d0

BOOTPROT = static # Start type (another dynamic is dhcp)

BROADCAST = 192.168.1.222 # BROADCAST address

HWADDR = 00: 06: 5B: FE: DF: 7C # hardware Mac address

IPADDR = 192.168.1.54 # IP Address

NETMASK = 255.255.255.0 # Subnet Mask

NETWORK = 192.168.0.0 # NETWORK address

GATEWAY = 192.168.0.1 # GATEWAY address

ONBOOT = yes # Start or not

TYPE = Ethernet # network TYPE

# Restart an Eni

[Root @ Demon proc] # service network restart

Closing interface eth0: device status: 3 (disconnect) [OK]

Disable the loop interface: [OK]

Pop-up loop interface: [OK]

Pop-up page: eth0: active connection status: Active

Active connection path:/org/freedesktop/NetworkManager/ActiveConnection/12

Status: Activated

Connection activated [OK]

2. Dynamic IP settings

# First, open the NIC configuration file:

[Root @ Demon proc] # vim/etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE = eth0 # specify the DEVICE name

UUID = 1bc2ebe3-0b0c-4a67-89eb-9214a7bd97d0

BOOTPROT = dhcp # Start type

BROADCAST = 192.168.1.222 # BROADCAST address

HWADDR = 00: 06: 5B: FE: DF: 7C # hardware Mac address

ONBOOT = yes # Start or not

TYPE = Ethernet # network TYPE

# Restart an Eni

[Root @ Demon proc] # service network restart

Closing interface eth0: device status: 3 (disconnect) [OK]

Disable the loop interface: [OK]

Pop-up loop interface: [OK]

Pop-up page: eth0: active connection status: Active

Active connection path:/org/freedesktop/NetworkManager/ActiveConnection/12

Status: Activated

Connection activated [OK]