Adding a list of hosts that you must be able to talk to in order to use the PoC.

ee-installer/src/install-poc.md

@@ -23,7 +23,7 @@ to be considered and this guide will work through them:
 - [Machine Size](install-poc.md#machine-size)
 - [Operating System](install-poc.md#operating-system)
 - [Users](install-poc.md#users)
-- [Network Ports to Open](install-poc.md#network-ports-to-open)
+- [Network Specifics](install-poc.md#network-specifics)
 - [Postgresql Database](install-poc.md#postgresql-database)
 - [TURN Server](install-poc.md#turn-server)
 - [SSL Certificates](install-poc.md#ssl-certificates)
@@ -140,7 +140,7 @@ EL: (as a normal user)
 pip3 install signedjson --user
 ```
 
-### Network Ports to Open
+### Network Specifics
 
 Element Enterprise On-Premise needs to bind and serve content over:
 
@@ -158,6 +158,16 @@ sudo systemctl stop firewalld
 sudo systemctl disable firewalld
 ```
 
+Further, you need to make sure that your host is able to access the following hosts on the internet:
+
+```
+api.snapcraft.io
+gitlab.matrix.org
+pypi.org
+```
+
+Further, you will also need to make sure that your host can access your distributions' package repositories. As these hostnames can vary, it is beyond the scope of this documentation to enumerate them.
+
 ### Users
 
 The installer requires that you run it as a non-root user who has sudo
@@ -481,7 +491,7 @@ Let’s review! Have you considered:
 - [Hostnames/DNS](install-poc.md#hostnamesdns)
 - [Operating System](install-poc.md#operating-system)
 - [Users](install-poc.md#users)
-- [Network Ports to Open](install-poc.md#network-ports-to-open)
+- [Network Specifics](install-poc.md#network-specifics)
 - [Postgresql Database](install-poc.md#postgresql-database)
 - [TURN Server](install-poc.md#turn-server)
 - [SSL Certificates](install-poc.md#ssl-certificates)