How to use 20 Netstat commands for Linux Network Management
- netstat is a useful tool for checking your network configuration and activity. It is in fact a collection of several tools lumped together
- netstat tool is very important and much useful for Linux network administrators as well as system administrators to monitor and troubleshoot their network-related problems and determine network traffic performance.
- netstat is one of the most basic network service debugging tools, telling you what ports are open and whether any programs are listening on ports.
This article shows usages of netstat command with their examples which may be useful in daily operation.
1. Listing all the LISTENING Ports of TCP and UDP Connections
Listing all ports (both TCP and UDP) using option: netstat -a
2. Listing TCP Ports connections
Listing only TCP (Transmission Control Protocol) port connections using: netstat -at
3. Listing UDP Ports connections
Listing only UDP (User Datagram Protocol ) port connections using: netstat -au
4. Listing all LISTENING Connections
Listing all active listening ports connections with: netstat -l
5. Listing all TCP Listening Ports
Listing all active listening TCP ports by using option: netstat -lt
6. Listing all UDP Listening Ports
Listing all active listening UDP ports by using option: netstat -lu
7. Listing all UNIX Listening Ports
8. Showing Statistics by Protocol
Displays statistics by protocol. By default, statistics are shown for the TCP, UDP, ICMP, and IP protocols. The -s parameter can be used to specify a set of protocols
9. Showing Statistics by TCP Protocol
Showing statistics of only TCP protocol by using option: netstat -st
10. Showing Statistics by UDP Protocol
11. Displaying Service name with PID
Displaying service name with their PID number, using option netstat -tp will display “PID/Program Name“
12. Displaying Promiscuous Mode
Displaying Promiscuous mode with -ac switch, netstat print the selected information or refresh screen every five seconds. The default screen refreshes every second
netstat -ac 5 | grep tcp
13. Displaying Kernel IP routing
Display Kernel IP routing table with netstat and route command
14. Showing Network Interface Transactions
Showing network interface packet transactions including both transferring and receiving packets with MTU size
15. Showing Kernel Interface Table
Showing Kernel interface table, similar to ifconfig command
16. Displaying IPv4 and IPv6 Information
Displays multicast group membership information for both IPv4 and IPv6
17. Print Netstat Information Continuously
To get netstat information every few seconds, then use the following command, it will print netstat information continuously, say every few seconds.
18. Finding non-supportive Address
Finding un-configured address families with some useful information
19. Finding Listening Programs
Find out how many listening programs running on a port
netstat -ap | grep http
20. Displaying RAW Network Statistics
netstat --statistics --raw
That’s it, If you are looking for more information and options about the netstat command, refer to netstat manual docs or use the man netstat command to know all the information.
If we’ve missed anything in the list, please inform us using our comment section below. So, we could keep updating this list based on your comments.