Other Help Topics :: DSL Server question

Hi, i have the dsl version 3.1 as server.
The following ports are forwarded by our router+accespoint:
80: http
21: ftp server
22: ssh remote control
3306: mysql remote control

My question is: do i need a firewall or anti-virus for linux? And so yes: wich are there??

Because there is a router in between i don't know, but i also don't know for anti-virus...

Grtz Themuzz

original here.