Re: Port 123 and ipv6

["Karl E. Jorgensen" <karl@jorgensen.org.uk>]

Hi

On Tue, Jan 28, 2014 at 03:00:43PM +0800, lina wrote:
> >> I read something online, and wonder:
> >> 1] shall I close the port 123
> > 
> > Probably you should, unless you're providing ntp to some other hosts.s
> 
> I have disabled the ntp. Here is other two things:
> 
> 1] about port 631, can I turn it off? since I only print very
> occasionally, I don't know the real purpose of cupsd;
> 
> 2] I don't know why the dhclient occupy several ports to listen, and
> what's a little annoying is that seems my IP address barely changed even
> I reboot after one night.
> 
> 
> # netstat -nltup
> Active Internet connections (only servers)
> Proto Recv-Q Send-Q Local Address           Foreign Address
> State       PID/Program name
> tcp        0      0 127.0.0.1:631           0.0.0.0:*
> LISTEN      3288/cupsd
> tcp        0      0 127.0.0.1:25            0.0.0.0:*
> LISTEN      3776/exim4
> tcp        0      0 127.0.0.1:2628          0.0.0.0:*
> LISTEN      3268/0
> tcp6       0      0 ::1:631                 :::*
> LISTEN      3288/cupsd

cups is only listening on port 631 on localhost (=127.0.0.1 in ipv4
and ::1 in ipv6) - it is not open to the outside world.

-- 
Karl E. Jorgensen