squid318

we having squid 3.1.8 . it is configured by default but it is not working as fast like direct connection. can any body help to make it squid fast.
server dell poweredge T410
Processor speed one 2.26GHZ quad-core processor
bus speed 4.80 GT/S
hardisk capcity is 279GB
mem 4GB
Platform solaris 11 oracle
webmin version 1.580
internet connection speed is 6MB
15 number of users need to be used but future it may be increased to 25 numbers.
some websites not opening quickly but it take time too open.

The following error was encountered while trying to retrieve the URL: http://www.amway.in/
Unable to determine IP address from host name www.amway.in
The DNS server returned:
Server Failure: The name server was unable to process this query.
when opening some sites iam facing above said error. plz help