Example of Squid Proxy config for Crowbar that uses a CNTLM proxy

squid.conf

acl localhost src 127.0.0.1/32
acl localhost src ::1
acl to_localhost dst 127.0.0.0/8
acl to_localhost dst 0.0.0.0/32
acl to_localhost dst ::1
acl localnet src 192.168.0.0/16         # RFC1918 possible internal network
acl localnet src 172.16.0.0/12          # For Docker VMs running locally.
acl to_localnet dst 192.168.0.0/16
acl to_localnet dst fe80::/10
acl to_localnet dst 172.16.0.0/12
acl to_localnet dst 10.0.0.0/8
acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines

acl SSL_ports port 443
acl Safe_ports port 80          # http
acl Safe_ports port 21          # ftp
acl Safe_ports port 443         # https
acl Safe_ports port 70          # gopher
acl Safe_ports port 210         # wais
acl Safe_ports port 1025-65535  # unregistered ports
acl Safe_ports port 280         # http-mgmt
acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http
acl CONNECT method CONNECT

# Allow PURGE from localhost.
acl PURGE method PURGE
http_access allow PURGE localhost
http_access deny PURGE

#http_access allow manager localhost
#http_access deny manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow localnet
http_access allow localhost
http_access deny all
http_port 8123
always_direct allow to_localnet
always_direct allow to_localhost
cache_peer 127.0.0.1 parent 3128 0 default
never_direct allow all
cache_mem 256 MB
maximum_object_size_in_memory 512 KB
memory_replacement_policy lru
cache_replacement_policy heap LFUDA
cache_dir aufs /var/cache/squid 17000 16 256
maximum_object_size 1 GB
coredump_dir /var/cache/squid
refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern -i (/cgi-bin/|\?) 0     0%      0
refresh_pattern (Release|Packages(.gz)*)$      0       20%     2880
refresh_pattern (\.deb|\.udeb|\.rpm)$   129600 100% 129600
refresh_pattern .               0       20%     4320