Ports

April 25, 2020 by dev Leave a Comment

Check Opened and Closed Ports on Linux

List opened ports with protocol name :
```
netstat --listen --tcp
```

List opened ports with protocol number :
```
netstat --listen --tcp -n
```

Check a Port 587 is Not Blocked. For example, Port 25
```
telnet yourdomain.tld 25
```
- 220 response confirm port not blocked
- Unable to connect or Connection refused confirm port blocked.