Bem rápido... abra um shell e:

Passo 1
# apt-get install tor privoxy proxychains

Passo 2
Configure o privoxy
# nano /etc/privoxy/config

No fim do arquivo config, insira a linha:
forward-socks4a / localhost:9050 .

detalhe depois da porta 9050 espaço em branco e ponto.

Passo 3
# privoxy /etc/privoxy/config

Passo 4
# tor

Passo 5
#proxychains nmap -sT -PN -n -sV -p21,25,80 10.0.2.15

ProxyChains-3.1 (ProxyChains - TCP and DNS through proxy server. HTTP and SOCKS)

Starting Nmap 5.35DC1 ( Nmap - Free Security Scanner For Network Exploration & Security Audits. ) at 2010-08-30 11:34 BRT
|S-chain|-<>-127.0.0.1:9050-<><>-10.0.2.15:21-<--denied
|S-chain|-<>-127.0.0.1:9050-<><>-10.0.2.15:80-<--denied
|S-chain|-<>-127.0.0.1:9050-<><>-10.0.2.15:25-<--denied
Nmap scan report for 10.0.2.15
Host is up (0.038s latency).
PORT STATE SERVICE VERSION
21/tcp closed ftp
25/tcp closed smtp
80/tcp closed http

Service detection performed. Please report any incorrect results at Nmap - Free Security Scanner For Network Exploration & Security Audits.. org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 0.70 seconds

OBS: -<--denied = Porta Bloqueada/Filtrada e -<--OK = Porta Aberta

Espero ter ajudado

@firebitsbr