Welcome to the LinuxFocus September/October 2003 issue

Mozilla and netscape-7 users: Watch out! When you download a page for translation and you use File->Save page as..., then select in the dialog box "Files of type: Html only" and not "Files of type: complete". Using "complete" modifies the page source code!. If you have some kind of translation page where people can get the articles then please add this note to warn people.

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The LinuxFocus Tip

You don't need nessus or other scanners to check all open ports on an ordinary computer without firewall. It is enough to just run "netstat -a". The output will look similar to the one below and you can see imediately in the colum "Local Address" which ports are available for connections:
netstat -a
Proto Recv-Q Send-Q Local Address   Foreign Address   State      
tcp        0      0 *:login         *:*               LISTEN      
tcp        0      0 *:shell         *:*               LISTEN      
tcp        0      0 *:pop2          *:*               LISTEN      
tcp        0      0 *:pop3          *:*               LISTEN      
tcp        0      0 *:imap2         *:*               LISTEN      
tcp        0      0 *:www           *:*               LISTEN      
tcp        0      0 *:domain        *:*               LISTEN      
...printout continues here...
You can even go one step further and check which program opens a port with the command socklist (normally part of a package called procinfo):
type  port      inode     uid    pid   fd  name
tcp    513       1007       0    448    5  xinetd
tcp    514       1006       0    448    4  xinetd
tcp   6000       1133       0    680    0  X
tcp     80       1076       0    643   16  httpd
...printout continues here...
netstat works on any Unix system but socklist is a Linux specific feature.

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