Below is the complete process to enable access to the pfSense's server sshd (ssh, port 22) from a private network...
Using option 8 ("8) Shell") turning off the firewall with the command...
pfctl -d
... and access pfSense server through the ssh (port 22)...
ssh root@<PFSENSE_SRV_IP>
... using the initial password "pfsense".
TIP: We recommend changing the initial password.
Using option 12 ("12) PHP shell + pfSense tools") perform the commands...
unset($config['interfaces']['wan']['blockpriv']);
write_config();
exec;
... and exit...
exit
Using option 8 ("8) Shell") again, add a rule to allow access through port 22 on the wan interface...
easyrule pass wan tcp any any 22
TIP: The "any any" parameters allow you to restrict the source IP and destination IP respectively.
NOTE: The above command will turn on the firewall (same as pfctl -e) and this will drop the ssh connection (port 22), but the ssh connection will be allowed.
PLUS: For more explanations about why private networks and loopback addresses are blocked by default on WAN here Block private networks - What does that do, what is it used for ? and here Address Allocation for Private Internets.
Thanks! =D
[Ref(s).: pfSense - Enable ssh (port 22) access through the WAN using terminal/console/shell ]