Merge pull request snori74#114 from EagTG/patch-1

Update 09.md

Author: snori74

09.md

@@ -17,13 +17,13 @@ There are a wide range of options that can be used with *ss*, but first try: *ss
 
 The output lines show which ports are open on which interfaces:
 
-    ss -ltp
-    State       Recv-Q       Send-Q              Local Address:Port             Peer Address:Port       
-    LISTEN      0            128                 127.0.0.53%lo:53                    0.0.0.0:*          
-    LISTEN      0            128                       0.0.0.0:22                    0.0.0.0:*          
-    LISTEN      0            128                             *:80                          *:*          
-    LISTEN      0            128                          [::]:22                       [::]:*              
-    
+    sudo ss -ltp
+    State   Recv-Q  Send-Q   Local Address:Port     Peer Address:Port  Process
+    LISTEN  0       4096     127.0.0.53%lo:domain        0.0.0.0:*      users:(("systemd-resolve",pid=364,fd=13))
+    LISTEN  0       128            0.0.0.0:ssh           0.0.0.0:*      users:(("sshd",pid=625,fd=3))
+    LISTEN  0       128               [::]:ssh              [::]:*      users:(("sshd",pid=625,fd=4))
+    LISTEN  0       511                  *:http                *:*      users:(("apache2",pid=106630,fd=4),("apache2",pid=106629,fd=4),("apache2",pid=106627,fd=4))         
+
 The network notation can be a little confusing, but the lines above show ports 80 and 22 open "to the world" on all local IP addresses - and port 53 (DNS) open only on a special local address.
 
 Now install `nmap` with `apt install`. This works rather differently, actively probing 1,000 or more ports to check whether they're open. It's most famously used to scan remote machines - please don't - but it's also very handy to check your own configuration, by scanning your server: