some url unreachable

[salah khater <sal2com@xxxxxxxxx>]

hi all

I have squid3.1.6 with no authintication ,
when I go to some sites like http://www.debian.org/ site it give me error (101) network unreachable .
and in squid access log I get tcp-miss/503 .

I can resolve the site with my cach dns (pdnsd service).
what couse this problem?
os debian squeeze

salah khater