Here is the list of IPs that you can whitelist against the firewall.
156.70.25.202
192.174.80.197
156.70.25.200
156.70.24.90
156.70.3.45
147.253.212.49
192.174.90.235
192.174.80.250
156.70.5.9
156.70.23.185
156.70.46.255
192.174.85.35
156.70.47.92
156.70.25.203
156.70.5.12
192.174.90.233
156.70.47.93
156.70.23.183
156.70.23.184
156.70.121.6
192.174.80.241
192.174.93.180
147.253.210.51
147.253.215.156
156.70.47.90
192.174.90.234
192.174.90.236
156.70.25.201
192.174.86.56
156.70.46.254
147.253.216.16
156.70.47.95
156.70.47.94
156.70.2.4
147.253.223.144
156.70.23.182
156.70.47.91
192.174.85.36