hey all,

i nmap'd my linode and got the following:

PORT STATE SERVICE
22/tcp open ssh
623/tcp filtered unknown
664/tcp filtered unknown
1720/tcp filtered H.323/Q.931


Seeing as I don't know what ports 623, 667 and 1720 are, I'd like to know if I need to worry about them.

thank you
n

Ports can appear in three states from the outside: open, closed, and filtered.

Open means the machine accepted the connection.

Closed means the machine refused the connection.

Filtered means no response was received at all.

Your "unknown" ports are all filtered, which in this case means they're being blocked by the datacenter your particular Linode is in.