From: http://ubuntuserverguide.com/2012/05/how-to-install-and-configure-proxy-server-with-squid3-on-ubuntu-server-12-04-lts.html

/etc/squid3/squid.conf
#
# DNS OPTIONS
# ==========
#
dns_timeout 10 seconds
dns_nameservers 192.168.1.1 8.8.8.8 8.8.4.4 # DNS Server
#

From:

grep -v "^#" /etc/squid/squid.conf | sed -e '/^$/d'

From: https://forum.pfsense.org/index.php?topic=57230.0

So that would be my suggestion:

    Hard disk cache size 15GB
    Hard disk cache system aufs or ufs (increase vfs.read like you did already) Test which 
    performs better
    Memory cache size 32MB
    Minimum object size 16KB (I set it to 64 KB because I do not want that so many small 
    files will be cached. This increases HDD read/write and my WAN bandwidth allows that
     to download such small files directly from the web and not from squid)
    Maximum object size 1GB ( ServicePacks do have sizeses until 1GB. If you do not want 
    to cache all kind of service packs than probably a size of 256MB will be enough to get 
    most of the available updates in cache)
    Maximum object size in RAM 2MB (In RAM I would like to have only small files which could 
    be served very fast. I do not want to have a 100MB file in RAM which wastes much space 
    and could be served fast enough even from HDD)
    Memory replacement policy LRU (RAM should cache actual objects)
    Cache replacement policy Heap LFUDA (what to cache servicepacks and big files on HDD)

From: http://wiki.squid-cache.org/SquidFaq/SquidMemory#How_much_memory_do_I_need_in_my_Squid_server.3F

As a rule of thumb on Squid uses approximately 10 MB of RAM per GB of the total of all cache_dirs 
(more on 64 bit servers such as Alpha), plus your cache_mem setting and about an additional 10-20MB. 
It is recommended to have at least twice this amount of physical RAM available on your Squid server.

From: http://curl-loader.sourceforge.net/

curl-loader (also known as "omes-nik" and "davilka") is an open-source tool written in C-language, 
simulating application load and application behavior of thousands and tens of thousand HTTP/HTTPS 
and FTP/FTPS clients, each with its own source IP-address. In contrast to other tools curl-loader 
is using real C-written client protocol stacks, namely, HTTP and FTP stacks of libcurl and TLS/SSL 
of openssl, and simulates user behavior with support for login and authentication flavors.

The goal of the project is to deliver a powerful and flexible open-source testing solution as a real 
alternative to Spirent Avalanche and IXIA IxLoad.

From: http://www.comfsm.fm/computing/squid/FAQ-6.html

These are taken from RFC 2616 and verified for Squid. Squid-2 uses almost all codes except 
307 (Temporary Redirect), 416 (Request Range Not Satisfiable), and 417 (Expectation Failed).

From: http://wiki.squid-cache.org/SquidFaq/SquidLogs

The Squid result code is composed of several tags (separated by underscore characters) which 
describe the response sent to the client.