Understanding netstat output

[luketomes]

I ran netstat the other day after installing my firewall and was surprised to find some active ports that I didn't know about. Heres the output of netstat-

[localhost:~] luke% netstat

Active Internet connections
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp 0 0 210-55-241-119.d.49153 64.212.171.241.6660 ESTABLISHED
tcp 0 0 localhost.1033 localhost.883 ESTABLISHED
tcp 0 0 localhost.883 localhost.1033 ESTABLISHED
tcp 0 60 localhost.1033 localhost.820 ESTABLISHED
tcp 0 0 localhost.820 localhost.1033 ESTABLISHED
tcp 0 0 localhost.1033 *.* LISTEN
udp 0 0 localhost.49153 localhost.853
udp 0 0 localhost.49152 localhost.853
udp 0 0 localhost.1033 *.*


Now I know the first port is IRC,

What are all the other ports for? (1033,883 etc)
Why are the active?

If I run nmap they dont show on the scan as listening, so I was assuming they were internal ports used by applications, but as they say "to ASSUME is to make an ASS out of U and ME".

Any commments would be appreciated.

Luke Tomes.