need just add to squid.conf manually
http_port 3128
``` for listening at all interfaces ipv4 and ipv6
or```
http_port [ipv6]:3128
```or listening additional on ipv6 interface
and restart service by```
service squid.sh restart
But after tune setting of Squid via pfSence GUI this settings overwritten to only ipv4.
For prevent it add http_port to area for custom options of setting Squid pfSence GUI.
After it in squid.conf http_port option added was after ```
Package Integration
Tested at pfSence 2.3.