I have distributed an iOS Enterprise App. We can't use MDM. On iPhone, after the manual installation of the Enterprise App, the manual trust of the Enterprise Developer works correctly if the device is fully connected to Internet. But if the iPhone is behind a firewall the manual Trust of the Enterprise Developer fails with the message "...An Internet Connection is required". The firewall is configured to allow connections to https://ppq.apple.com , and the connection on the same iPhone works if we open this address in Safari (the label "Ok" is displayed"). We have followed the instructions in this article: https://support.apple.com/en-us/HT204460 Please can you tell me what are the mandatory connections to allow in the Firewall to allow the Trust of the Enterprise Developer from iPhone? Allowing only https://ppq.apple.com, use1-ppq-ext-prod.apple.com,  use1-ppq-ext-prod.apple.com is not enough. From the firewall we have got the following log of all the Apple IP Address that the iPhone has tried to contact during the Trust of the Enterprise Developer and there are many others IP Address that are not  ppq.apple.com: code-block 17.33.201.70 (ppq.apple.com - Apple address ALLOWED by Firewall) 17.250.80.144 (Apple IP BLOCKED by Firewall) 17.250.80.146 (Apple IP BLOCKED by Firewall) 17.250.80.166 (Apple IP BLOCKED by Firewall) 17.250.80.138 (Apple IP BLOCKED by Firewall) 17.250.80.135 (Apple IP BLOCKED by Firewall) 17.250.80.142 (Apple IP BLOCKED by Firewall) 17.250.80.108 (Apple IP BLOCKED by Firewall) 17.250.80.10 (Apple IP BLOCKED by Firewall) 17.250.80.9 (Apple IP BLOCKED by Firewall) 17.57.172.11 (Apple IP BLOCKED by Firewall) 17.250.80.7 (Apple IP BLOCKED by Firewall) 17.250.80.149 (Apple IP BLOCKED by Firewall) 17.250.80.115 (Apple IP BLOCKED by Firewall) 17.250.80.168 (Apple IP BLOCKED by Firewall) 17.250.80.104 (Apple IP BLOCKED by Firewall) 17.57.172.10 (Apple IP BLOCKED by Firewall) 17.250.80.113 (Apple IP BLOCKED by Firewall) 17.33.202.170 (use1-ppq-ext-prod.apple.com - Apple address ALLOWED by Firewall) 17.33.200.235 (use1-ppq-ext-prod.apple.com - Apple address ALLOWED by Firewall) 17.57.146.54 (Apple IP BLOCKED by Firewall) 17.57.146.56 (Apple IP BLOCKED by Firewall) 17.57.146.55 (Apple IP BLOCKED by Firewall) 17.57.146.57 (Apple IP BLOCKED by Firewall) 17.111.103.19 (humb-old.apple.com - Apple address BLOCKED by Firewall) 17.253.79.202 (dedus1-vip-bx-002.aaplimg.com - Apple address BLOCKED by Firewall) 17.250.80.199 (Apple IP BLOCKED by Firewall) 17.250.80.197 (Apple IP BLOCKED by Firewall) 17.250.80.200 (Apple IP BLOCKED by Firewall) 17.250.80.212 (Apple IP BLOCKED by Firewall) 17.250.80.214 (Apple IP BLOCKED by Firewall) 17.250.80.228 (Apple IP BLOCKED by Firewall) 17.253.79.201 (dedus1-vip-bx-001.aaplimg.com - Apple address BLOCKED by Firewall) 17.250.80.180 (Apple IP BLOCKED by Firewall) 17.250.80.164 (Apple IP BLOCKED by Firewall) 17.250.80.134 (Apple IP BLOCKED by Firewall) 17.250.80.106 (Apple IP BLOCKED by Firewall) 17.250.80.170 (Apple IP BLOCKED by Firewall) 17.250.80.105 (Apple IP BLOCKED by Firewall) 17.250.80.167 (Apple IP BLOCKED by Firewall) 17.250.80.11 (Apple IP BLOCKED by Firewall) 17.250.80.110 (Apple IP BLOCKED by Firewall) 17.250.80.165 (Apple IP BLOCKED by Firewall) 17.250.80.179 (Apple IP BLOCKED by Firewall) 17.250.80.172 (Apple IP BLOCKED by Firewall) 17.250.80.8 (Apple IP BLOCKED by Firewall) 17.250.80.148 (Apple IP BLOCKED by Firewall) 17.250.80.150 (Apple IP BLOCKED by Firewall) 17.250.80.109 (Apple IP BLOCKED by Firewall) 17.250.80.101 (Apple IP BLOCKED by Firewall) 17.57.146.170 (Apple IP BLOCKED by Firewall) 17.57.146.174 (Apple IP BLOCKED by Firewall) 17.57.146.172 (Apple IP BLOCKED by Firewall) 17.57.146.171 (Apple IP BLOCKED by Firewall) 17.57.146.175 (Apple IP BLOCKED by Firewall) 17.57.146.162 (Apple IP BLOCKED by Firewall) 17.57.146.173 (Apple IP BLOCKED by Firewall) 17.57.146.163 (Apple IP BLOCKED by Firewall) 17.253.57.212 (defra3-vip-bx-012.aaplimg.com - Apple address BLOCKED by Firewall) 17.253.57.211 (defra3-vip-bx-011.aaplimg.com - Apple address BLOCKED by Firewall)