which port to close on firewall?

[DHDesign]

i recently got this in an email from our host provider for a dedicated server with a netscreen5 firewall...these are the current settings on the firewall:

Trust to Untrust: Allow ANY

Untrust to Trust: Allow FTP
Untrust to Trust: Allow SMTP
Untrust to Trust: Allow DNS
Untrust to Trust: Allow HTTP
Untrust to Trust: Allow HTTPS
Untrust to Trust: Allow POP3
Untrust to Trust: Allow SSH
Untrust to Trust: Allow Telnet
Untrust to Trust: Allow SI*
Untrust to Trust: Allow Plesk*

Now we are supposed to inform them of which ports to close and which IP addresses to ban, but how do you go about doing this? What should we restrict, which ports do we close and wat ipaddresses do we block?

any and all help is much appreciated. thanks!

[NANO3]

You have to tell you ISP which ports to close and open?

Is this a home network or a wide network??

[Theros]

Just close anything you dont need? :D

[NANO3]

The only thing I doubt you need is TelNet

[Jeff Wheeler]

Allow SSH, POP3, HTTP, HTTPS if you intend to have an ssl cert, DNS, SMTP, and FTP.