Hi everybody, I am trying to use an external_acl_type to be able to filter internet traffic according to specific User-agent headers and destination (let's say you have the right to browse facebook only by using Firefox). this is my external acl: external_acl_type getheaders %{User-Agent} %DST /etc/squid3/getheaders acl myacl external getheaders http_access allow myacl this is my getheaders program: (I runned it, and there are no permissions problem) #!/bin/sh read agent read DST date=`date` echo "$date $agent" >> /var/log/squid3/headers.log echo "$DST" >> /var/log/squid3/headers.log echo "OK" exit 1 and this is what I get in the debug when I try to access facebook: 2009/04/16 21:17:16.481| aclMatchExternal: acl="getheaders" 2009/04/16 21:17:16.481| aclMatchExternal: getheaders("Mozilla/5.0%20...............0Version/4.0%20Safari/528.16 www.facebook.com") = lookup needed 2009/04/16 21:17:16.481| externalAclLookup: lookup in 'getheaders' for 'Mozilla/5.0%20(Macintosh;%20U;%20In...........Version/4.0%20Safari/528.16 www.facebook.com' 2009/04/16 21:17:16.481| externalAclLookup: looking up for 'Mozilla/5.0%20(Macintosh;%20U;%20..............)%20Version/4.0%20Safari/528.16 www.facebook.com' in 'getheaders'. 2009/04/16 21:17:16.481| helperDispatch: Request sent to getheaders #1, 167 bytes 2009/04/16 21:17:16.482| externalAclLookup: will wait for the result of 'Mozilla/5.0%20(Macintosh...........0Safari/528.16 www.facebook.com' in 'getheaders' (ch=0x85a4760). Apparently squid is waiting for a domain lookup that my getheaders program should do. I am a bit lost as I thought that the only reply options are OK/ERR As I didn't find anything on google, if anybody has a clue, I would appreciate the share! :-) I am running the latest squid3 on debian Thank you, Julien