net work command

1.nmcli

# nmcli dev status
DEVICE      TYPE      STATE        CONNECTION
virbr0      bridge    connected    virbr0  
tun0        tun       connected    tun0    
wlp2s0      wifi      connected    soju    
enp1s0      ethernet  unavailable  --      
lo          loopback  unmanaged    --      
virbr0-nic  tap       unmanaged    --

#nmcli con show or
#nmcli c s
#ip a

NAME               UUID                                  TYPE             DEVICE
A                      66add4bf-d621-4e06-a462-f5552012e60d  vpn              --  
Germany-Darmstadt  d81ac3a2-1933-4f0e-b4d3-3353c5a93811  vpn              --  
B                      5c80d51e-69ed-4352-a970-3990e872919c  vpn              --  
Ais Fibre          432558f5-0a6b-4b2c-844d-c47e088735d4  802-11-wireless  --  
Net Mobile         b32f2e69-3b7b-4393-bbe3-8be11ec9d021  802-3-ethernet   --  
AiS FTTH           c55bbcb0-dee3-42bf-84ad-d1bb4da53e62  802-11-wireless  --  
@NYK               e78ca4b0-a2de-43a5-a402-89eac0ccf40e  802-3-ethernet   --  
Customer           364694a8-641b-4ea4-b117-5406c92e173c  802-11-wireless  --  
C                        c46e5d01-7cae-4042-8906-78ed4f593c51  802-11-wireless  --  
virbr0             5db0c606-007f-4b4f-b9e1-fc1ec10d5979  bridge           virbr0

Check speed network card
#ethtool enp4s6(network card)

#ethtool enp4s6(network card) |grep Speed
#ethtool enp4s6(network card) |grep -i speed

#mii-tools enp4s6(network card)

#dmesg |grep enp4s6(network card)
#dmesg |grep -i duplex

Ref:

configure-network-connections-using-nmcli-tool-in-linux

2. Check all Interface Network status
 

#for i in $( ls /sys/class/net ); do echo -n $i; ethtool $i | grep Link\ d; done

 Ref:
how-to-detect-whether-a-physical-cable-is-connected-to-network-card-slot-on-linux

3. vnstat for monitor network traffic
yum install vnstat

vnstat -i network interface
Ref: fedora-linux-install-vnstat-network-traffic-monitor

4.