Utilizing netstat command to check your Linux server network performance

Here’s some of the netstat command to check your network performance or behavior in your Linux server.

• Identified FIN_WAIT1, FOREIGN, SYNC_RECV, LAST_ACK, TIME_WAIT, LISTEN and ESTABLISHED  Connections 
  #netstat -nat | awk ‘{print $6}’ | sort | uniq -c | sort -n
  
• Identified established and time_wait connections state
  #netstat -etna|grep -i establi|wc -l
  
  Or
  #netstat -tupen |wc -l
  
  See the difference?
• Identified unique connection type
  • Tracking connection type
    #netstat -n -p | grep SYN_REC | sort -u
  • Get all ip address involved in the connection above
    #netstat -n -p | grep SYN_REC | awk ‘{print $5}’ | awk -F: ‘{print $1}’
  • Get all ip address that SYN_REC connection
    #netstat -ntu | awk ‘{print $5}’ | cut -d: -f1 | sort | uniq -c | sort -n
  • Calculate the number of connection from each unique ip address
    # netstat -anp |grep ‘tcp|udp’ | awk ‘{print $5}’ | cut -d: -f1 | sort | uniq -c | sort -n
  • Counting connection for TCP or UDP to the server
    # netstat -ntu | grep ESTAB | awk ‘{print $5}’ | cut -d: -f1 | sort | uniq -c | sort -nr
    
  • Get only ESTABLISHED connection of all connection with each ip count
    # netstat -plan|grep :80|awk {‘print $5’}|cut -d: -f 1|sort|uniq -c|sort -nk 1
    

Hope this helpfull.