vi /usr/local/etc/squid/squid.conf

Bueno, tampoco funciona, cargo el archivo de configuración, edito dicho archivo, guardo lo editado, me dirijo hacia el "Proxy server" doy clic en "Save" y se pierden lo agregado en dicho texto de configuración.  :-[

Saludos.

no estoy seguro que funcione pero verifica la edicion del archivo desde la gui del pfsense y no via consola.

en: diagnostic -> edit file

das la ruta: /usr/local/etc/squid/squid.conf

lo cargas y en mi caso:

# Do not edit manually !
http_port 192.168.2.1:3128
http_port 127.0.0.1:80 transparent
icp_port 0

pid_filename /var/run/squid.pid
cache_effective_user proxy
cache_effective_group proxy
error_directory /usr/local/etc/squid/errors/Spanish
icon_directory /usr/local/etc/squid/icons
visible_hostname Casitas Cache
cache_mgr vampiwifi@gmail.com
access_log /var/squid/log/access.log
cache_log /var/squid/log/cache.log
cache_store_log none
logfile_rotate 2
shutdown_lifetime 3 seconds
# Allow local network(s) on interface(s)
acl localnet src  192.168.2.0/255.255.255.0
uri_whitespace strip

cache_mem 512 MB
maximum_object_size_in_memory 32 KB
memory_replacement_policy heap GDSF
cache_replacement_policy heap LFUDA
cache_dir null /tmp
minimum_object_size 0 KB
maximum_object_size 400 KB
offline_mode on
cache_swap_low 90
cache_swap_high 95

# No redirector configured

# Setup some default acls
acl all src 0.0.0.0/0.0.0.0
acl localhost src 127.0.0.1/255.255.255.255
acl safeports port 21 70 80 210 280 443 488 563 591 631 777 901  3128 1025-65535
acl sslports port 443 563 
acl manager proto cache_object
acl purge method PURGE
acl connect method CONNECT
acl dynamic urlpath_regex cgi-bin \?
acl allowed_subnets src 192.168.2.0/24 
acl blacklist dstdom_regex -i "/var/squid/acl/blacklist.acl"
cache deny dynamic
http_access allow manager localhost

http_access deny manager
http_access allow purge localhost
http_access deny purge
http_access deny !safeports
http_access deny CONNECT !sslports

# Always allow localhost connections
http_access allow localhost

quick_abort_min 0 KB
quick_abort_max 0 KB
request_body_max_size 2048 KB
reply_body_max_size 20480000 allow all
delay_pools 1
delay_class 1 2
delay_parameters 1 256000/256000 204800/204800
delay_initial_bucket_level 100
# Throttle extensions matched in the url
acl throttle_exts urlpath_regex -i "/var/squid/acl/throttle_exts.acl"
delay_access 1 allow throttle_exts
delay_access 1 deny all

# Block access to blacklist domains
http_access deny blacklist
# Setup allowed acls
# Allow local network(s) on interface(s)
http_access allow allowed_subnets
http_access allow localnet
# Default block all to be sure
http_access deny all

lo editas y lo gravas.
luego cuentanos si se dejo editar.