[squid-users] IP Maskerading

Hi all!
I've got a little security problem; checking on this address
http://checkip.dyndns.org/, I've found out that my clients IPs are
perfectly visible by the outside world.
How can I get rid of that and either pass the NAT address or a fake one ?
Thanks

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|            __    __          | Valter DAL BO
|           /  \ /| |'-.       | e-mail: dalbo@tesco.it
|          .\__/ || |   |      |
|       _ /  `._ \|_|_.-'      | Tesco TS S.p.A.
|      | /  \__.`=._) (_       | http://www.tesco.it
|      |/ ._/  |"""""""""|     |
|      |'.  `\ |         |     | tel.: +390113011711
|      ;"""/ / |         |     | fax : +390113140362
|       ) /_/| |.-------.|     | mobile: +393357707810
|      '  `-`' "         "     | C.so Tazzoli 10137 Torino ITALY
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