Доброго времени суток.
Имеем в squid.conf:
...
ftp_user anonymous@
ftp_passive off
ftp_sanitycheck off
...
acl Safe_ports port 80          # http
acl Safe_ports port 21          # ftp
acl Safe_ports port 20          # ftp
acl Safe_ports port 443         # https

acl CONNECT method CONNECT

http_access allow level2ip
http_access allow level1ip Safe_ports
http_access deny !Safe_ports
http_access deny CONNECT !Safe_ports
http_access deny all

Получаем при использовании:
Squid sent the following FTP command:
    NLST
and then received this reply
    Use PORT or PASV first.

Где я наломал дров?