Closing ports in jail with ipfw

[marcel]

Le Mon, 05 Dec 2016 08:31:19 +0800,
Ernie Luzar <luzar722 at gmail.com> a écrit :

> marcel wrote:
> > Hi there,
> > 
> > I've created a jail and when I do a nmap on his IP, I can see that
> > port 25 and 22 are open but I don't want. So i've tried to create
> > an IPFW rule by adding 'ipwf -q add 00290 deny all from router to
> > jail' to my host ipfw conf file and applied it but ports jail are
> > still open. How can I close or open the ports of my jail ?
> > 
> > Thanks !  
> 
> You can not run nmap on the host targeting the jails ip. Doing so
> only shows you open ports on the host. You have to run nmap from a
> computer on a different public ip address targeting the public ip
> address assigned to the jail. If jail is using a non-routeable ip
> address, nmap is useless in looking for jail open ports.

Hi ! Sorry for silence, I was not able to answer. Yeah I understand,
maybe netstat -an in jail is more useful ? When I do that I see port 25
and 514 are open but if I haven't looked yet what is this port 514 I
imagine both of these ports are not closable (or it's not advised) 
isnt'it ?