Is my Redhat 9 safe with all this ports Open?

Goodday.

I have a Aztech 4 port router a RH9 behind it.

I did a NMAP on the Router and i got this results:

Interesting ports on
adslXXX.dynXXX.pacific.net.sg (210.24.XXX.XXX.):

(The 1599 ports scanned but not shown below are in state: closed)
Port State Service
80/tcp open http
255/tcp open unknown

Are this ports safe or do i have to close them.

And i did a NMAP scan on my RH9

Interesting ports on (10.0.0.X):
(The 1594 ports scanned but not shown below are in state: closed)
Port State Service
22/tcp open ssh
80/tcp open http
111/tcp open sunrpc
139/tcp open netbios-ssn
443/tcp open https
901/tcp open samba-swat
6000/tcp open X11

By the way i have amule running, i wonder if the ports are reflected here.

Please advise on what uncessary port i have to close to secure my PC .
Thanks.
Oh yah... Additional info I am also sharing files between my RH9 and Win 2000.