All SIP signalling from babelforce will come from sip.babelforce.com, IP 188.8.131.52 and from 184.108.40.206.
So the first step to prepare your network is to allow 220.127.116.11 /sip.babelforce.com and 18.104.22.168 in your firewall.
If you get softphones from babelforce, we will configure them for you, so that they already have settings to allow for them to find the right path through your network. We can also adapt the settings so that at each login, your softphone will automatically pick up the latest.
If you connect other deskphones or IP phones, then you will get account details from us.
The best thing to do is to setup the phones and then test inbound and outbound calls while observing the traffic in your network.
The following diagram illustrates how the communication works for inbound calls:
1. Your phone or your softphone will register with sip.babelforce.com / 22.214.171.124 using a port on your external IP, e.g. 126.96.36.199:1158. It will stay registered from this IP and port for some time. Note the port 1158 is an example, the phone/softphone will get a port dependent on its settings and the mapping between your external ports and the internal IP and ports used on the computers and devices.
2. When a call comes in to your babelforce number (hotline, office number ...), sip.babelforce.com / 188.8.131.52 will send SIP signals to the user/agent phone, on 184.108.40.206:1158 in this example. This is why 220.127.116.11 must be allowed in your firewall
3. The softphone will often have its own internal IP and port. So you must ensure that your mapping from external to internal IPs and ports is working right.
The best thing to do is set up a test case like above in your babelforce account. Then do the inbound calls and outbound calls and check that the traffic is correctly traversing your network. You can also find the technical details and requirements for connecting phone devices and using babelforce telephone services in the following article: https://babelforce.zendesk.com/hc/en-us/articles/204265795-Connecting-Phones-via-SIP-Technical-details-and-requirements